Project import generated by Copybara.

GitOrigin-RevId: 2c3273caa153ee8eb5786bc8141b85b859e7efd7

third_party/nixpkgs/.editorconfig

@@ -0,0 +1,28 @@
+# EditorConfig configuration for nixpkgs
+# http://EditorConfig.org
+
+# Top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file, utf-8 charset
+[*]
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+charset = utf-8
+
+# see https://nixos.org/nixpkgs/manual/#chap-conventions
+
+# Match nix/ruby/docbook files, set indent to spaces with width of two
+[*.{nix,rb,xml}]
+indent_style = space
+indent_size = 2
+
+# Match shell/python/perl scripts, set indent to spaces with width of four
+[*.{sh,py,pl}]
+indent_style = space
+indent_size = 4
+
+# Match diffs, avoid to trim trailing whitespace
+[*.{diff,patch}]
+trim_trailing_whitespace = false

third_party/nixpkgs/.gitattributes

@@ -0,0 +1,16 @@
+**/deps.nix linguist-generated
+**/node-packages.nix linguist-generated
+
+pkgs/applications/editors/emacs-modes/*-generated.nix linguist-generated
+pkgs/development/r-modules/*-packages.nix linguist-generated
+pkgs/development/haskell-modules/hackage-packages.nix linguist-generated
+pkgs/development/beam-modules/hex-packages.nix linguist-generated
+
+doc/** linguist-documentation
+doc/default.nix linguist-documentation=false
+
+nixos/doc/** linguist-documentation
+nixos/doc/default.nix linguist-documentation=false
+
+nixos/modules/module-list.nix merge=union
+# pkgs/top-level/all-packages.nix merge=union

third_party/nixpkgs/.github/CODEOWNERS

@@ -0,0 +1,181 @@
+# CODEOWNERS file
+#
+# This file is used to describe who owns what in this repository. This file does not
+# replace `meta.maintainers` but is instead used for other things than derivations
+# and modules, like documentation, package sets, and other assets.
+#
+# For documentation on this file, see https://help.github.com/articles/about-codeowners/
+# Mentioned users will get code review requests.
+
+# This file
+/.github/CODEOWNERS @edolstra
+
+# Libraries
+/lib                        @edolstra @nbp @infinisil
+/lib/systems                @nbp @ericson2314 @matthewbauer
+/lib/generators.nix         @edolstra @nbp @Profpatsch
+/lib/cli.nix                @edolstra @nbp @Profpatsch
+/lib/debug.nix              @edolstra @nbp @Profpatsch
+/lib/asserts.nix            @edolstra @nbp @Profpatsch
+
+# Nixpkgs Internals
+/default.nix                          @nbp
+/pkgs/top-level/default.nix           @nbp @Ericson2314
+/pkgs/top-level/impure.nix            @nbp @Ericson2314
+/pkgs/top-level/stage.nix             @nbp @Ericson2314 @matthewbauer
+/pkgs/top-level/splice.nix            @Ericson2314 @matthewbauer
+/pkgs/top-level/release-cross.nix     @Ericson2314 @matthewbauer
+/pkgs/stdenv/generic                  @Ericson2314 @matthewbauer
+/pkgs/stdenv/cross                    @Ericson2314 @matthewbauer
+/pkgs/build-support/cc-wrapper        @Ericson2314 @orivej
+/pkgs/build-support/bintools-wrapper  @Ericson2314 @orivej
+/pkgs/build-support/setup-hooks       @Ericson2314
+
+# Nixpkgs build-support
+/pkgs/build-support/writers @lassulus @Profpatsch
+
+# NixOS Internals
+/nixos/default.nix          @nbp @infinisil
+/nixos/lib/from-env.nix     @nbp @infinisil
+/nixos/lib/eval-config.nix  @nbp @infinisil
+/nixos/doc/manual/configuration/abstractions.xml      @nbp
+/nixos/doc/manual/configuration/config-file.xml       @nbp
+/nixos/doc/manual/configuration/config-syntax.xml     @nbp
+/nixos/doc/manual/configuration/modularity.xml        @nbp
+/nixos/doc/manual/development/assertions.xml          @nbp
+/nixos/doc/manual/development/meta-attributes.xml     @nbp
+/nixos/doc/manual/development/option-declarations.xml @nbp
+/nixos/doc/manual/development/option-def.xml          @nbp
+/nixos/doc/manual/development/option-types.xml        @nbp
+/nixos/doc/manual/development/replace-modules.xml     @nbp
+/nixos/doc/manual/development/writing-modules.xml     @nbp
+/nixos/doc/manual/man-nixos-option.xml                @nbp
+/nixos/modules/installer/tools/nixos-option.sh        @nbp
+
+# NixOS integration test driver
+/nixos/lib/test-driver  @tfc
+
+# Python-related code and docs
+/maintainers/scripts/update-python-libraries	@FRidh
+/pkgs/top-level/python-packages.nix     @FRidh @jonringer
+/pkgs/development/interpreters/python   @FRidh
+/pkgs/development/python-modules        @FRidh @jonringer
+/doc/languages-frameworks/python.section.md     @FRidh
+
+# Haskell
+/pkgs/development/compilers/ghc                       @cdepillabout
+/pkgs/development/haskell-modules		      @cdepillabout
+/pkgs/development/haskell-modules/default.nix	      @cdepillabout
+/pkgs/development/haskell-modules/generic-builder.nix @cdepillabout
+/pkgs/development/haskell-modules/hoogle.nix	      @cdepillabout
+
+# Perl
+/pkgs/development/interpreters/perl @volth
+/pkgs/top-level/perl-packages.nix   @volth
+/pkgs/development/perl-modules      @volth
+
+# R
+/pkgs/applications/science/math/R   @peti
+/pkgs/development/r-modules         @peti
+
+# Ruby
+/pkgs/development/interpreters/ruby @alyssais
+/pkgs/development/ruby-modules      @alyssais
+
+# Rust
+/pkgs/development/compilers/rust @Mic92 @LnL7
+/pkgs/build-support/rust @andir
+
+# Darwin-related
+/pkgs/stdenv/darwin         @NixOS/darwin-maintainers
+/pkgs/os-specific/darwin    @NixOS/darwin-maintainers
+
+# C compilers
+/pkgs/development/compilers/gcc @matthewbauer
+/pkgs/development/compilers/llvm @matthewbauer
+
+# Compatibility stuff
+/pkgs/top-level/unix-tools.nix @matthewbauer
+/pkgs/development/tools/xcbuild @matthewbauer
+
+# Beam-related (Erlang, Elixir, LFE, etc)
+/pkgs/development/beam-modules                  @gleber
+/pkgs/development/interpreters/erlang           @gleber
+/pkgs/development/interpreters/lfe              @gleber
+/pkgs/development/interpreters/elixir           @gleber
+/pkgs/development/tools/build-managers/rebar    @gleber
+/pkgs/development/tools/build-managers/rebar3   @gleber
+/pkgs/development/tools/erlang                  @gleber
+
+# Jetbrains
+/pkgs/applications/editors/jetbrains @edwtjo
+
+# Eclipse
+/pkgs/applications/editors/eclipse @rycee
+
+# Licenses
+/lib/licenses.nix @alyssais
+
+# Qt / KDE
+/pkgs/applications/kde @ttuegel
+/pkgs/desktops/plasma-5 @ttuegel
+/pkgs/development/libraries/kde-frameworks @ttuegel
+/pkgs/development/libraries/qt-5 @ttuegel
+
+# PostgreSQL and related stuff
+/pkgs/servers/sql/postgresql @thoughtpolice
+/nixos/modules/services/databases/postgresql.xml @thoughtpolice
+/nixos/modules/services/databases/postgresql.nix @thoughtpolice
+/nixos/tests/postgresql.nix @thoughtpolice
+
+# Hardened profile & related modules
+/nixos/modules/profiles/hardened.nix @joachifm
+/nixos/modules/security/hidepid.nix @joachifm
+/nixos/modules/security/lock-kernel-modules.nix @joachifm
+/nixos/modules/security/misc.nix @joachifm
+/nixos/tests/hardened.nix @joachifm
+/pkgs/os-specific/linux/kernel/hardened-config.nix @joachifm
+
+# Network Time Daemons
+/pkgs/tools/networking/chrony @thoughtpolice
+/pkgs/tools/networking/ntp @thoughtpolice
+/pkgs/tools/networking/openntpd @thoughtpolice
+/nixos/modules/services/networking/ntp @thoughtpolice
+
+# Dhall
+/pkgs/development/dhall-modules      @Gabriel439 @Profpatsch
+/pkgs/development/interpreters/dhall @Gabriel439 @Profpatsch
+
+# Idris
+/pkgs/development/idris-modules @Infinisil
+
+# Bazel
+/pkgs/development/tools/build-managers/bazel @mboes @Profpatsch
+
+# NixOS modules for e-mail and dns services
+/nixos/modules/services/mail/mailman.nix    @peti
+/nixos/modules/services/mail/postfix.nix    @peti
+/nixos/modules/services/networking/bind.nix @peti
+/nixos/modules/services/mail/rspamd.nix     @peti
+
+# Emacs
+/pkgs/applications/editors/emacs-modes @adisbladis
+/pkgs/applications/editors/emacs       @adisbladis
+/pkgs/top-level/emacs-packages.nix     @adisbladis
+
+# VimPlugins
+/pkgs/misc/vim-plugins         @jonringer @softinio
+
+# VsCode Extensions
+/pkgs/misc/vscode-extensions   @jonringer
+
+# Prometheus exporter modules and tests
+/nixos/modules/services/monitoring/prometheus/exporters.nix  @WilliButz
+/nixos/modules/services/monitoring/prometheus/exporters.xml  @WilliButz
+/nixos/tests/prometheus-exporters.nix                        @WilliButz
+
+# PHP
+/doc/languages-frameworks/php.section.md @etu
+/pkgs/development/interpreters/php       @etu
+/pkgs/top-level/php-packages.nix         @etu
+/pkgs/build-support/build-pecl.nix       @etu

third_party/nixpkgs/.github/CONTRIBUTING.md

@@ -0,0 +1,62 @@
+# How to contribute
+
+Note: contributing implies licensing those contributions
+under the terms of [COPYING](../COPYING), which is an MIT-like license.
+
+## Opening issues
+
+* Make sure you have a [GitHub account](https://github.com/signup/free)
+* Make sure there is no open issue on the topic
+* [Submit a new issue](https://github.com/NixOS/nixpkgs/issues/new/choose) by choosing the kind of topic and fill out the template
+
+## Submitting changes
+
+* Format the commit messages in the following way:
+
+  ```
+  (pkg-name | nixos/<module>): (from -> to | init at version | refactor | etc)
+
+  (Motivation for change. Additional information.)
+  ```
+
+  For consistency, there should not be a period at the end of the commit message's summary line (the first line of the commit message).
+
+  Examples:
+
+  * nginx: init at 2.0.1
+  * firefox: 54.0.1 -> 55.0
+  * nixos/hydra: add bazBaz option
+
+    Dual baz behavior is needed to do foo.
+  * nixos/nginx: refactor config generation
+
+    The old config generation system used impure shell scripts and could break in specific circumstances (see #1234).
+
+* `meta.description` should:
+  * Be capitalized.
+  * Not start with the package name.
+  * Not have a period at the end.
+* `meta.license` must be set and fit the upstream license.
+  * If there is no upstream license, `meta.license` should default to `stdenv.lib.licenses.unfree`.
+* `meta.maintainers` must be set.
+
+See the nixpkgs manual for more details on [standard meta-attributes](https://nixos.org/nixpkgs/manual/#sec-standard-meta-attributes) and on how to [submit changes to nixpkgs](https://nixos.org/nixpkgs/manual/#chap-submitting-changes).
+
+## Writing good commit messages
+
+In addition to writing properly formatted commit messages, it's important to include relevant information so other developers can later understand *why* a change was made. While this information usually can be found by digging code, mailing list/Discourse archives, pull request discussions or upstream changes, it may require a lot of work.
+
+For package version upgrades and such a one-line commit message is usually sufficient.
+
+## Backporting changes
+
+To [backport a change into a release branch](https://nixos.org/nixpkgs/manual/#submitting-changes-stable-release-branches):
+
+1. Take note of the commit in which the change was introduced into `master`.
+2. Check out the target _release branch_, e.g. `release-20.03`. Do not use a _channel branch_ like `nixos-20.03` or `nixpkgs-20.03`.
+3. Use `git cherry-pick -x <original commit>`.
+4. Open your backport PR. Make sure to select the release branch (e.g. `release-20.03`) as the target branch of the PR, and link to the PR in which the original change was made to `master`.
+
+## Reviewing contributions
+
+See the nixpkgs manual for more details on how to [Review contributions](https://nixos.org/nixpkgs/manual/#chap-reviewing-contributions).

third_party/nixpkgs/.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,11 @@
+## Issue description
+
+
+
+### Steps to reproduce
+
+
+
+## Technical details
+
+Please run `nix-shell -p nix-info --run "nix-info -m"` and paste the result.

third_party/nixpkgs/.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,43 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: '0.kind: bug'
+assignees: ''
+
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+Steps to reproduce the behavior:
+1. ...
+2. ...
+3. ...
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem.
+
+**Additional context**
+Add any other context about the problem here.
+
+**Notify maintainers**
+<!--
+Please @ people who are in the `meta.maintainers` list of the offending package or module.
+If in doubt, check `git blame` for whoever last touched something.
+-->
+
+**Metadata**
+Please run `nix-shell -p nix-info --run "nix-info -m"` and paste the result.
+
+Maintainer information:
+```yaml
+# a list of nixpkgs attributes affected by the problem
+attribute:
+# a list of nixos modules affected by the problem
+module:
+```

third_party/nixpkgs/.github/ISSUE_TEMPLATE/packaging_request.md

@@ -0,0 +1,18 @@
+---
+name: Packaging requests
+about: For packages that are missing
+title: ''
+labels: '0.kind: packaging request'
+assignees: ''
+
+---
+
+**Project description**
+_describe the project a little_
+
+**Metadata**
+
+* homepage URL:
+* source URL:
+* license: mit, bsd, gpl2+ , ...
+* platforms: unix, linux, darwin, ...

third_party/nixpkgs/.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,19 @@
+<!-- Nixpkgs has a lot of new incoming Pull Requests, but not enough people to review this constant stream. Even if you aren't a committer, we would appreciate reviews of other PRs, especially simple ones like package updates. Just testing the relevant package/service and leaving a comment saying what you tested, how you tested it and whether it worked would be great. List of open PRs: <https://github.com/NixOS/nixpkgs/pulls>, for more about reviewing contributions: <https://hydra.nixos.org/job/nixpkgs/trunk/manual/latest/download/1/nixpkgs/manual.html#chap-reviewing-contributions>. Reviewing isn't mandatory, but it would help out a lot and reduce the average time-to-merge for all of us. Thanks a lot if you do! -->
+###### Motivation for this change
+
+
+###### Things done
+
+<!-- Please check what applies. Note that these are not hard requirements but merely serve as information for reviewers. -->
+
+- [ ] Tested using sandboxing ([nix.useSandbox](http://nixos.org/nixos/manual/options.html#opt-nix.useSandbox) on NixOS, or option `sandbox` in [`nix.conf`](http://nixos.org/nix/manual/#sec-conf-file) on non-NixOS linux)
+- Built on platform(s)
+   - [ ] NixOS
+   - [ ] macOS
+   - [ ] other Linux distributions
+- [ ] Tested via one or more NixOS test(s) if existing and applicable for the change (look inside [nixos/tests](https://github.com/NixOS/nixpkgs/blob/master/nixos/tests))
+- [ ] Tested compilation of all pkgs that depend on this change using `nix-shell -p nixpkgs-review --run "nixpkgs-review wip"`
+- [ ] Tested execution of all binary files (usually in `./result/bin/`)
+- [ ] Determined the impact on package closure size (by running `nix path-info -S` before and after)
+- [ ] Ensured that relevant documentation is up to date
+- [ ] Fits [CONTRIBUTING.md](https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md).

third_party/nixpkgs/.github/stale.yml

@@ -0,0 +1,32 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 180
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: false
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - 1.severity: security
+# Label to use when marking an issue as stale
+staleLabel: 2.status: stale
+# Comment to post when marking an issue as stale. Set to `false` to disable
+markComment: >
+  Thank you for your contributions.
+
+  This has been automatically marked as stale because it has had no
+  activity for 180 days.
+
+  If this is still important to you, we ask that you leave a
+  comment below. Your comment can be as simple as "still important
+  to me". This lets people see that at least one person still cares
+  about this. Someone will have to do this at most twice a year if
+  there is no other activity.
+
+  Here are suggestions that might help resolve this more quickly:
+
+  1. Search for maintainers and people that previously touched the
+     related code and @ mention them in a comment.
+  2. Ask on the [NixOS Discourse](https://discourse.nixos.org/).
+  3. Ask on the [#nixos channel](irc://irc.freenode.net/#nixos) on
+     [irc.freenode.net](https://freenode.net).
+
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: false

third_party/nixpkgs/.gitignore

@@ -0,0 +1,21 @@
+*~
+,*
+.*.swp
+.*.swo
+result
+result-*
+/doc/NEWS.html
+/doc/NEWS.txt
+/doc/manual.html
+/doc/manual.pdf
+.version-suffix
+
+.DS_Store
+.mypy_cache
+
+/pkgs/development/libraries/qt-5/*/tmp/
+/pkgs/desktops/kde-5/*/tmp/
+/pkgs/development/mobile/androidenv/xml/*
+
+# generated by pkgs/common-updater/update-script.nix
+update-git-commits.txt

third_party/nixpkgs/.version

@@ -0,0 +1 @@
+20.09

third_party/nixpkgs/COPYING

@@ -0,0 +1,20 @@
+Copyright (c) 2003-2020 Eelco Dolstra and the Nixpkgs/NixOS contributors
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

third_party/nixpkgs/README.md

@@ -0,0 +1,112 @@
+<p align="center">
+  <a href="https://nixos.org/nixos"><img src="https://nixos.org/logo/nixos-hires.png" width="500px" alt="NixOS logo" /></a>
+</p>
+
+<p align="center">
+  <a href="https://www.codetriage.com/nixos/nixpkgs"><img src="https://www.codetriage.com/nixos/nixpkgs/badges/users.svg" alt="Code Triagers badge" /></a>
+  <a href="https://opencollective.com/nixos"><img src="https://opencollective.com/nixos/tiers/supporter/badge.svg?label=Supporter&color=brightgreen" alt="Open Collective supporters" /></a>
+</p>
+
+[Nixpkgs](https://github.com/nixos/nixpkgs) is a collection of over
+40,000 software packages that can be installed with the
+[Nix](https://nixos.org/nix/) package manager. It also implements
+[NixOS](https://nixos.org/nixos/), a purely-functional Linux distribution.
+
+# Manuals
+
+* [NixOS Manual](https://nixos.org/nixos/manual) - how to install, configure, and maintain a purely-functional Linux distribution
+* [Nixpkgs Manual](https://nixos.org/nixpkgs/manual/) - contributing to Nixpkgs and using programming-language-specific Nix expressions
+* [Nix Package Manager Manual](https://nixos.org/nix/manual) - how to write Nix expressions (programs), and how to use Nix command line tools
+
+# Community
+
+* [Discourse Forum](https://discourse.nixos.org/)
+* [IRC - #nixos on freenode.net](irc://irc.freenode.net/#nixos)
+* [NixOS Weekly](https://weekly.nixos.org/)
+* [Community-maintained wiki](https://nixos.wiki/)
+* [Community-maintained list of ways to get in touch](https://nixos.wiki/wiki/Get_In_Touch#Chat) (Discord, Matrix, Telegram, other IRC channels, etc.)
+
+# Other Project Repositories
+
+The sources of all official Nix-related projects are in the [NixOS
+organization on GitHub](https://github.com/NixOS/). Here are some of
+the main ones:
+
+* [Nix](https://github.com/NixOS/nix) - the purely functional package manager
+* [NixOps](https://github.com/NixOS/nixops) - the tool to remotely deploy NixOS machines
+* [Nix RFCs](https://github.com/NixOS/rfcs) - the formal process for making substantial changes to the community
+* [NixOS homepage](https://github.com/NixOS/nixos-homepage) - the [NixOS.org](https://nixos.org) website
+* [hydra](https://github.com/NixOS/hydra) - our continuous integration system
+* [NixOS Artwork](https://github.com/NixOS/nixos-artwork) - NixOS artwork
+
+# Continuous Integration and Distribution
+
+Nixpkgs and NixOS are built and tested by our continuous integration
+system, [Hydra](https://hydra.nixos.org/).
+
+* [Continuous package builds for unstable/master](https://hydra.nixos.org/jobset/nixos/trunk-combined)
+* [Continuous package builds for the NixOS 20.03 release](https://hydra.nixos.org/jobset/nixos/release-20.03)
+* [Tests for unstable/master](https://hydra.nixos.org/job/nixos/trunk-combined/tested#tabs-constituents)
+* [Tests for the NixOS 20.03 release](https://hydra.nixos.org/job/nixos/release-20.03/tested#tabs-constituents)
+
+Artifacts successfully built with Hydra are published to cache at
+https://cache.nixos.org/. When successful build and test criteria are
+met, the Nixpkgs expressions are distributed via [Nix
+channels](https://nixos.org/nix/manual/#sec-channels).
+
+# Contributing
+
+Nixpkgs is among the most active projects on GitHub. While thousands
+of open issues and pull requests might seem a lot at first, it helps
+consider it in the context of the scope of the project. Nixpkgs
+describes how to build over 40,000 pieces of software and implements a
+Linux distribution. The [GitHub Insights](https://github.com/NixOS/nixpkgs/pulse)
+page gives a sense of the project activity.
+
+Community contributions are always welcome through GitHub Issues and
+Pull Requests. When pull requests are made, our tooling automation bot,
+[OfBorg](https://github.com/NixOS/ofborg) will perform various checks
+to help ensure expression quality.
+
+The *Nixpkgs maintainers* are people who have assigned themselves to
+maintain specific individual packages. We encourage people who care
+about a package to assign themselves as a maintainer. When a pull
+request is made against a package, OfBorg will notify the appropriate
+maintainer(s). The *Nixpkgs committers* are people who have been given
+permission to merge.
+
+Most contributions are based on and merged into these branches:
+
+* `master` is the main branch where all small contributions go
+* `staging` is branched from master, changes that have a big impact on
+  Hydra builds go to this branch
+* `staging-next` is branched from staging and only fixes to stabilize
+  and security fixes with a big impact on Hydra builds should be
+  contributed to this branch. This branch is merged into master when
+  deemed of sufficiently high quality
+
+For more information about contributing to the project, please visit
+the [contributing page](https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md).
+
+# Donations
+
+The infrastructure for NixOS and related projects is maintained by a
+nonprofit organization, the [NixOS
+Foundation](https://nixos.org/nixos/foundation.html). To ensure the
+continuity and expansion of the NixOS infrastructure, we are looking
+for donations to our organization.
+
+You can donate to the NixOS foundation by using Open Collective:
+
+<a href="https://opencollective.com/nixos#support"><img src="https://opencollective.com/nixos/tiers/supporter.svg?width=890" /></a>
+
+# License
+
+Nixpkgs is licensed under the [MIT License](COPYING).
+
+Note: MIT license does not apply to the packages built by Nixpkgs,
+merely to the files in this repository (the Nix expressions, build
+scripts, NixOS modules, etc.). It also might not apply to patches
+included in Nixpkgs, which may be derivative works of the packages to
+which they apply. The aforementioned artifacts are all covered by the
+licenses of the respective packages.

third_party/nixpkgs/default.nix

@@ -0,0 +1,28 @@
+let requiredVersion = import ./lib/minver.nix; in
+
+if ! builtins ? nixVersion || builtins.compareVersions requiredVersion builtins.nixVersion == 1 then
+
+  abort ''
+
+    This version of Nixpkgs requires Nix >= ${requiredVersion}, please upgrade:
+
+    - If you are running NixOS, `nixos-rebuild' can be used to upgrade your system.
+
+    - Alternatively, with Nix > 2.0 `nix upgrade-nix' can be used to imperatively
+      upgrade Nix. You may use `nix-env --version' to check which version you have.
+
+    - If you installed Nix using the install script (https://nixos.org/nix/install),
+      it is safe to upgrade by running it again:
+
+          curl https://nixos.org/nix/install | sh
+
+    For more information, please see the NixOS release notes at
+    https://nixos.org/nixos/manual or locally at
+    ${toString ./nixos/doc/manual/release-notes}.
+
+    If you need further help, see https://nixos.org/nixos/support.html
+  ''
+
+else
+
+  import ./pkgs/top-level/impure.nix

third_party/nixpkgs/doc/.gitignore

@@ -0,0 +1,8 @@
+*.chapter.xml
+*.section.xml
+.version
+functions/library/generated
+functions/library/locations.xml
+highlightjs
+manual-full.xml
+out

third_party/nixpkgs/doc/Makefile

@@ -0,0 +1,110 @@
+MD_TARGETS=$(addsuffix .xml, $(basename $(wildcard ./*.md ./**/*.md)))
+
+.PHONY: all
+all: validate format out/html/index.html out/epub/manual.epub
+
+.PHONY: debug
+debug:
+	nix-shell --run "xmloscopy --docbook5 ./manual.xml ./manual-full.xml"
+
+.PHONY: format
+format: doc-support/result
+	find . -iname '*.xml' -type f | while read f; do \
+		echo $$f ;\
+		xmlformat --config-file "doc-support/result/xmlformat.conf" -i $$f ;\
+	done
+
+.PHONY: fix-misc-xml
+fix-misc-xml:
+	find . -iname '*.xml' -type f \
+		-exec ../nixos/doc/varlistentry-fixer.rb {} ';'
+
+.PHONY: clean
+clean:
+	rm -f ${MD_TARGETS} doc-support/result .version manual-full.xml functions/library/locations.xml functions/library/generated
+	rm -rf ./out/ ./highlightjs
+
+.PHONY: validate
+validate: manual-full.xml doc-support/result
+	jing doc-support/result/docbook.rng manual-full.xml
+
+out/html/index.html: doc-support/result manual-full.xml style.css highlightjs
+	mkdir -p out/html
+	xsltproc \
+		--nonet --xinclude \
+		--output $@ \
+		doc-support/result/xhtml.xsl \
+		./manual-full.xml
+
+	mkdir -p out/html/highlightjs/
+	cp -r highlightjs out/html/
+
+	cp ./overrides.css out/html/
+	cp ./style.css out/html/style.css
+
+	mkdir -p out/html/images/callouts
+	cp doc-support/result/xsl/docbook/images/callouts/*.svg out/html/images/callouts/
+	chmod u+w -R out/html/
+
+out/epub/manual.epub: manual-full.xml
+	mkdir -p out/epub/scratch
+	xsltproc --nonet \
+		--output out/epub/scratch/ \
+		doc-support/result/epub.xsl \
+		./manual-full.xml
+
+	cp ./overrides.css out/epub/scratch/OEBPS
+	cp ./style.css out/epub/scratch/OEBPS
+	mkdir -p out/epub/scratch/OEBPS/images/callouts/
+	cp doc-support/result/xsl/docbook/images/callouts/*.svg out/epub/scratch/OEBPS/images/callouts/
+	echo "application/epub+zip" > mimetype
+	zip -0Xq "out/epub/manual.epub" mimetype
+	rm mimetype
+	cd "out/epub/scratch/" && zip -Xr9D "../manual.epub" *
+	rm -rf "out/epub/scratch/"
+
+highlightjs: doc-support/result
+	mkdir -p highlightjs
+	cp -r doc-support/result/highlightjs/highlight.pack.js highlightjs/
+	cp -r doc-support/result/highlightjs/LICENSE highlightjs/
+	cp -r doc-support/result/highlightjs/mono-blue.css highlightjs/
+	cp -r doc-support/result/highlightjs/loader.js highlightjs/
+
+
+manual-full.xml: ${MD_TARGETS} .version functions/library/locations.xml functions/library/generated *.xml **/*.xml **/**/*.xml
+	xmllint --nonet --xinclude --noxincludenode manual.xml --output manual-full.xml
+
+.version: doc-support/result
+	ln -rfs ./doc-support/result/version .version
+
+doc-support/result: doc-support/default.nix
+	(cd doc-support; nix-build)
+
+functions/library/locations.xml: doc-support/result
+	ln -rfs ./doc-support/result/function-locations.xml functions/library/locations.xml
+
+functions/library/generated: doc-support/result
+	ln -rfs ./doc-support/result/function-docs functions/library/generated
+
+%.section.xml: %.section.md
+	pandoc $^ -w docbook \
+		-f markdown+smart \
+	  | sed -e 's|<ulink url=|<link xlink:href=|' \
+	      -e 's|</ulink>|</link>|' \
+	      -e 's|<sect. id=|<section xml:id=|' \
+	      -e 's|</sect[0-9]>|</section>|' \
+	      -e '1s| id=| xml:id=|' \
+	      -e '1s|\(<[^ ]* \)|\1xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" |' \
+	| cat  > $@
+
+%.chapter.xml: %.chapter.md
+	pandoc $^ -w docbook \
+		--top-level-division=chapter \
+		-f markdown+smart \
+	  | sed -e 's|<ulink url=|<link xlink:href=|' \
+	      -e 's|</ulink>|</link>|' \
+	      -e 's|<sect. id=|<section xml:id=|' \
+	      -e 's|</sect[0-9]>|</section>|' \
+	      -e '1s| id=| xml:id=|' \
+	      -e '1s|\(<[^ ]* \)|\1|' \
+	| cat  > $@

third_party/nixpkgs/doc/builders/fetchers.xml

@@ -0,0 +1,150 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-pkgs-fetchers">
+ <title>Fetchers</title>
+ <para>
+  When using Nix, you will frequently need to download source code and other files from the internet. Nixpkgs comes with a few helper functions that allow you to fetch fixed-output derivations in a structured way.
+ </para>
+ <para>
+  The two fetcher primitives are <function>fetchurl</function> and <function>fetchzip</function>. Both of these have two required arguments, a URL and a hash. The hash is typically <literal>sha256</literal>, although many more hash algorithms are supported. Nixpkgs contributors are currently recommended to use <literal>sha256</literal>. This hash will be used by Nix to identify your source. A typical usage of fetchurl is provided below.
+ </para>
+<programlisting><![CDATA[
+{ stdenv, fetchurl }:
+
+stdenv.mkDerivation {
+  name = "hello";
+  src = fetchurl {
+    url = "http://www.example.org/hello.tar.gz";
+    sha256 = "1111111111111111111111111111111111111111111111111111";
+  };
+}
+]]></programlisting>
+ <para>
+  The main difference between <function>fetchurl</function> and <function>fetchzip</function> is in how they store the contents. <function>fetchurl</function> will store the unaltered contents of the URL within the Nix store. <function>fetchzip</function> on the other hand will decompress the archive for you, making files and directories directly accessible in the future. <function>fetchzip</function> can only be used with archives. Despite the name, <function>fetchzip</function> is not limited to .zip files and can also be used with any tarball.
+ </para>
+ <para>
+  <function>fetchpatch</function> works very similarly to <function>fetchurl</function> with the same arguments expected. It expects patch files as a source and and performs normalization on them before computing the checksum. For example it will remove comments or other unstable parts that are sometimes added by version control systems and can change over time.
+ </para>
+ <para>
+  Other fetcher functions allow you to add source code directly from a VCS such as subversion or git. These are mostly straightforward names based on the name of the command used with the VCS system. Because they give you a working repository, they act most like <function>fetchzip</function>.
+ </para>
+ <variablelist>
+  <varlistentry>
+   <term>
+    <literal>fetchsvn</literal>
+   </term>
+   <listitem>
+    <para>
+     Used with Subversion. Expects <literal>url</literal> to a Subversion directory, <literal>rev</literal>, and <literal>sha256</literal>.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchgit</literal>
+   </term>
+   <listitem>
+    <para>
+     Used with Git. Expects <literal>url</literal> to a Git repo, <literal>rev</literal>, and <literal>sha256</literal>. <literal>rev</literal> in this case can be full the git commit id (SHA1 hash) or a tag name like <literal>refs/tags/v1.0</literal>.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchfossil</literal>
+   </term>
+   <listitem>
+    <para>
+     Used with Fossil. Expects <literal>url</literal> to a Fossil archive, <literal>rev</literal>, and <literal>sha256</literal>.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchcvs</literal>
+   </term>
+   <listitem>
+    <para>
+     Used with CVS. Expects <literal>cvsRoot</literal>, <literal>tag</literal>, and <literal>sha256</literal>.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchhg</literal>
+   </term>
+   <listitem>
+    <para>
+     Used with Mercurial. Expects <literal>url</literal>, <literal>rev</literal>, and <literal>sha256</literal>.
+    </para>
+   </listitem>
+  </varlistentry>
+ </variablelist>
+ <para>
+  A number of fetcher functions wrap part of <function>fetchurl</function> and <function>fetchzip</function>. They are mainly convenience functions intended for commonly used destinations of source code in Nixpkgs. These wrapper fetchers are listed below.
+ </para>
+ <variablelist>
+  <varlistentry>
+   <term>
+    <literal>fetchFromGitHub</literal>
+   </term>
+   <listitem>
+    <para>
+     <function>fetchFromGitHub</function> expects four arguments. <literal>owner</literal> is a string corresponding to the GitHub user or organization that controls this repository. <literal>repo</literal> corresponds to the name of the software repository. These are located at the top of every GitHub HTML page as <literal>owner</literal>/<literal>repo</literal>. <literal>rev</literal> corresponds to the Git commit hash or tag (e.g <literal>v1.0</literal>) that will be downloaded from Git. Finally, <literal>sha256</literal> corresponds to the hash of the extracted directory. Again, other hash algorithms are also available but <literal>sha256</literal> is currently preferred.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchFromGitLab</literal>
+   </term>
+   <listitem>
+    <para>
+     This is used with GitLab repositories. The arguments expected are very similar to fetchFromGitHub above.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchFromGitiles</literal>
+   </term>
+   <listitem>
+    <para>
+     This is used with Gitiles repositories. The arguments expected
+     are similar to fetchgit.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchFromBitbucket</literal>
+   </term>
+   <listitem>
+    <para>
+     This is used with BitBucket repositories. The arguments expected are very similar to fetchFromGitHub above.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchFromSavannah</literal>
+   </term>
+   <listitem>
+    <para>
+     This is used with Savannah repositories. The arguments expected are very similar to fetchFromGitHub above.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>fetchFromRepoOrCz</literal>
+   </term>
+   <listitem>
+    <para>
+     This is used with repo.or.cz repositories. The arguments expected are very similar to fetchFromGitHub above.
+    </para>
+   </listitem>
+  </varlistentry>
+ </variablelist>
+</chapter>

third_party/nixpkgs/doc/builders/images.xml

@@ -0,0 +1,12 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-images">
+ <title>Images</title>
+ <para>
+  This chapter describes tools for creating various types of images.
+ </para>
+ <xi:include href="images/appimagetools.xml" />
+ <xi:include href="images/dockertools.xml" />
+ <xi:include href="images/ocitools.xml" />
+ <xi:include href="images/snaptools.xml" />
+</chapter>

third_party/nixpkgs/doc/builders/images/appimagetools.xml

@@ -0,0 +1,102 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-pkgs-appimageTools">
+ <title>pkgs.appimageTools</title>
+
+ <para>
+  <varname>pkgs.appimageTools</varname> is a set of functions for extracting and wrapping <link xlink:href="https://appimage.org/">AppImage</link> files. They are meant to be used if traditional packaging from source is infeasible, or it would take too long. To quickly run an AppImage file, <literal>pkgs.appimage-run</literal> can be used as well.
+ </para>
+
+ <warning>
+  <para>
+   The <varname>appimageTools</varname> API is unstable and may be subject to backwards-incompatible changes in the future.
+  </para>
+ </warning>
+
+ <section xml:id="ssec-pkgs-appimageTools-formats">
+  <title>AppImage formats</title>
+
+  <para>
+   There are different formats for AppImages, see <link xlink:href="https://github.com/AppImage/AppImageSpec/blob/74ad9ca2f94bf864a4a0dac1f369dd4f00bd1c28/draft.md#image-format">the specification</link> for details.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Type 1 images are ISO 9660 files that are also ELF executables.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Type 2 images are ELF executables with an appended filesystem.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   They can be told apart with <command>file -k</command>:
+  </para>
+
+<screen>
+<prompt>$ </prompt>file -k type1.AppImage
+type1.AppImage: ELF 64-bit LSB executable, x86-64, version 1 (SYSV) ISO 9660 CD-ROM filesystem data 'AppImage' (Lepton 3.x), scale 0-0,
+spot sensor temperature 0.000000, unit celsius, color scheme 0, calibration: offset 0.000000, slope 0.000000, dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=d629f6099d2344ad82818172add1d38c5e11bc6d, stripped\012- data
+
+<prompt>$ </prompt>file -k type2.AppImage
+type2.AppImage: ELF 64-bit LSB executable, x86-64, version 1 (SYSV) (Lepton 3.x), scale 232-60668, spot sensor temperature -4.187500, color scheme 15, show scale bar, calibration: offset -0.000000, slope 0.000000 (Lepton 2.x), scale 4111-45000, spot sensor temperature 412442.250000, color scheme 3, minimum point enabled, calibration: offset -75402534979642766821519867692934234112.000000, slope 5815371847733706829839455140374904832.000000, dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=79dcc4e55a61c293c5e19edbd8d65b202842579f, stripped\012- data
+</screen>
+
+  <para>
+   Note how the type 1 AppImage is described as an <literal>ISO 9660 CD-ROM filesystem</literal>, and the type 2 AppImage is not.
+  </para>
+ </section>
+
+ <section xml:id="ssec-pkgs-appimageTools-wrapping">
+  <title>Wrapping</title>
+
+  <para>
+   Depending on the type of AppImage you're wrapping, you'll have to use <varname>wrapType1</varname> or <varname>wrapType2</varname>.
+  </para>
+
+<programlisting>
+appimageTools.wrapType2 { # or wrapType1
+  name = "patchwork"; <co xml:id='ex-appimageTools-wrapping-1' />
+  src = fetchurl { <co xml:id='ex-appimageTools-wrapping-2' />
+    url = "https://github.com/ssbc/patchwork/releases/download/v3.11.4/Patchwork-3.11.4-linux-x86_64.AppImage";
+    sha256 =  "1blsprpkvm0ws9b96gb36f0rbf8f5jgmw4x6dsb1kswr4ysf591s";
+  };
+  extraPkgs = pkgs: with pkgs; [ ]; <co xml:id='ex-appimageTools-wrapping-3' />
+}</programlisting>
+
+  <calloutlist>
+   <callout arearefs='ex-appimageTools-wrapping-1'>
+    <para>
+     <varname>name</varname> specifies the name of the resulting image.
+    </para>
+   </callout>
+   <callout arearefs='ex-appimageTools-wrapping-2'>
+    <para>
+     <varname>src</varname> specifies the AppImage file to extract.
+    </para>
+   </callout>
+   <callout arearefs='ex-appimageTools-wrapping-3'>
+    <para>
+     <varname>extraPkgs</varname> allows you to pass a function to include additional packages inside the FHS environment your AppImage is going to run in. There are a few ways to learn which dependencies an application needs:
+     <itemizedlist>
+      <listitem>
+       <para>
+        Looking through the extracted AppImage files, reading its scripts and running <command>patchelf</command> and <command>ldd</command> on its executables. This can also be done in <command>appimage-run</command>, by setting <command>APPIMAGE_DEBUG_EXEC=bash</command>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Running <command>strace -vfefile</command> on the wrapped executable, looking for libraries that can't be found.
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </callout>
+  </calloutlist>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/images/dockertools.xml

@@ -0,0 +1,478 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-pkgs-dockerTools">
+ <title>pkgs.dockerTools</title>
+
+ <para>
+  <varname>pkgs.dockerTools</varname> is a set of functions for creating and manipulating Docker images according to the <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#docker-image-specification-v120"> Docker Image Specification v1.2.0 </link>. Docker itself is not used to perform any of the operations done by these functions.
+ </para>
+
+ <section xml:id="ssec-pkgs-dockerTools-buildImage">
+  <title>buildImage</title>
+
+  <para>
+   This function is analogous to the <command>docker build</command> command, in that it can be used to build a Docker-compatible repository tarball containing a single image with one or multiple layers. As such, the result is suitable for being loaded in Docker with <command>docker load</command>.
+  </para>
+
+  <para>
+   The parameters of <varname>buildImage</varname> with relative example values are described below:
+  </para>
+
+  <example xml:id='ex-dockerTools-buildImage'>
+   <title>Docker build</title>
+<programlisting>
+buildImage {
+  name = "redis"; <co xml:id='ex-dockerTools-buildImage-1' />
+  tag = "latest"; <co xml:id='ex-dockerTools-buildImage-2' />
+
+  fromImage = someBaseImage; <co xml:id='ex-dockerTools-buildImage-3' />
+  fromImageName = null; <co xml:id='ex-dockerTools-buildImage-4' />
+  fromImageTag = "latest"; <co xml:id='ex-dockerTools-buildImage-5' />
+
+  contents = pkgs.redis; <co xml:id='ex-dockerTools-buildImage-6' />
+  runAsRoot = '' <co xml:id='ex-dockerTools-buildImage-runAsRoot' />
+    #!${pkgs.runtimeShell}
+    mkdir -p /data
+  '';
+
+  config = { <co xml:id='ex-dockerTools-buildImage-8' />
+    Cmd = [ "/bin/redis-server" ];
+    WorkingDir = "/data";
+    Volumes = {
+      "/data" = {};
+    };
+  };
+}
+</programlisting>
+  </example>
+
+  <para>
+   The above example will build a Docker image <literal>redis/latest</literal> from the given base image. Loading and running this image in Docker results in <literal>redis-server</literal> being started automatically.
+  </para>
+
+  <calloutlist>
+   <callout arearefs='ex-dockerTools-buildImage-1'>
+    <para>
+     <varname>name</varname> specifies the name of the resulting image. This is the only required argument for <varname>buildImage</varname>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-2'>
+    <para>
+     <varname>tag</varname> specifies the tag of the resulting image. By default it's <literal>null</literal>, which indicates that the nix output hash will be used as tag.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-3'>
+    <para>
+     <varname>fromImage</varname> is the repository tarball containing the base image. It must be a valid Docker image, such as exported by <command>docker save</command>. By default it's <literal>null</literal>, which can be seen as equivalent to <literal>FROM scratch</literal> of a <filename>Dockerfile</filename>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-4'>
+    <para>
+     <varname>fromImageName</varname> can be used to further specify the base image within the repository, in case it contains multiple images. By default it's <literal>null</literal>, in which case <varname>buildImage</varname> will peek the first image available in the repository.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-5'>
+    <para>
+     <varname>fromImageTag</varname> can be used to further specify the tag of the base image within the repository, in case an image contains multiple tags. By default it's <literal>null</literal>, in which case <varname>buildImage</varname> will peek the first tag available for the base image.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-6'>
+    <para>
+     <varname>contents</varname> is a derivation that will be copied in the new layer of the resulting image. This can be similarly seen as <command>ADD contents/ /</command> in a <filename>Dockerfile</filename>. By default it's <literal>null</literal>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-runAsRoot'>
+    <para>
+     <varname>runAsRoot</varname> is a bash script that will run as root in an environment that overlays the existing layers of the base image with the new resulting layer, including the previously copied <varname>contents</varname> derivation. This can be similarly seen as <command>RUN ...</command> in a <filename>Dockerfile</filename>.
+     <note>
+      <para>
+       Using this parameter requires the <literal>kvm</literal> device to be available.
+      </para>
+     </note>
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-8'>
+    <para>
+     <varname>config</varname> is used to specify the configuration of the containers that will be started off the built image in Docker. The available options are listed in the <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#image-json-field-descriptions"> Docker Image Specification v1.2.0 </link>.
+    </para>
+   </callout>
+  </calloutlist>
+
+  <para>
+   After the new layer has been created, its closure (to which <varname>contents</varname>, <varname>config</varname> and <varname>runAsRoot</varname> contribute) will be copied in the layer itself. Only new dependencies that are not already in the existing layers will be copied.
+  </para>
+
+  <para>
+   At the end of the process, only one new single layer will be produced and added to the resulting image.
+  </para>
+
+  <para>
+   The resulting repository will only list the single image <varname>image/tag</varname>. In the case of <xref linkend='ex-dockerTools-buildImage'/> it would be <varname>redis/latest</varname>.
+  </para>
+
+  <para>
+   It is possible to inspect the arguments with which an image was built using its <varname>buildArgs</varname> attribute.
+  </para>
+
+  <note>
+   <para>
+    If you see errors similar to <literal>getProtocolByName: does not exist (no such protocol name: tcp)</literal> you may need to add <literal>pkgs.iana-etc</literal> to <varname>contents</varname>.
+   </para>
+  </note>
+
+  <note>
+   <para>
+    If you see errors similar to <literal>Error_Protocol ("certificate has unknown CA",True,UnknownCa)</literal> you may need to add <literal>pkgs.cacert</literal> to <varname>contents</varname>.
+   </para>
+  </note>
+
+  <example xml:id="example-pkgs-dockerTools-buildImage-creation-date">
+   <title>Impurely Defining a Docker Layer's Creation Date</title>
+   <para>
+    By default <function>buildImage</function> will use a static date of one second past the UNIX Epoch. This allows <function>buildImage</function> to produce binary reproducible images. When listing images with <command>docker images</command>, the newly created images will be listed like this:
+   </para>
+<screen><![CDATA[
+$ docker images
+REPOSITORY   TAG      IMAGE ID       CREATED        SIZE
+hello        latest   08c791c7846e   48 years ago   25.2MB
+]]></screen>
+   <para>
+    You can break binary reproducibility but have a sorted, meaningful <literal>CREATED</literal> column by setting <literal>created</literal> to <literal>now</literal>.
+   </para>
+<programlisting><![CDATA[
+pkgs.dockerTools.buildImage {
+  name = "hello";
+  tag = "latest";
+  created = "now";
+  contents = pkgs.hello;
+
+  config.Cmd = [ "/bin/hello" ];
+}
+]]></programlisting>
+   <para>
+    and now the Docker CLI will display a reasonable date and sort the images as expected:
+<screen><![CDATA[
+$ docker images
+REPOSITORY   TAG      IMAGE ID       CREATED              SIZE
+hello        latest   de2bf4786de6   About a minute ago   25.2MB
+]]></screen>
+    however, the produced images will not be binary reproducible.
+   </para>
+  </example>
+ </section>
+
+ <section xml:id="ssec-pkgs-dockerTools-buildLayeredImage">
+  <title>buildLayeredImage</title>
+
+  <para>
+   Create a Docker image with many of the store paths being on their own layer to improve sharing between images.
+  </para>
+
+  <variablelist>
+   <varlistentry>
+    <term>
+     <varname>name</varname>
+    </term>
+    <listitem>
+     <para>
+      The name of the resulting image.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>tag</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Tag of the generated image.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> the output path's hash
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>contents</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Top level paths in the container. Either a single derivation, or a list of derivations.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> <literal>[]</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>config</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Run-time configuration of the container. A full list of the options are available at in the <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#image-json-field-descriptions"> Docker Image Specification v1.2.0 </link>.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> <literal>{}</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>created</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Date and time the layers were created. Follows the same <literal>now</literal> exception supported by <literal>buildImage</literal>.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> <literal>1970-01-01T00:00:01Z</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>maxLayers</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Maximum number of layers to create.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> <literal>100</literal>
+     </para>
+     <para>
+      <emphasis>Maximum:</emphasis> <literal>125</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>extraCommands</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Shell commands to run while building the final layer, without access to most of the layer contents. Changes to this layer are "on top" of all the other layers, so can create additional directories and files.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+
+  <section xml:id="dockerTools-buildLayeredImage-arg-contents">
+   <title>Behavior of <varname>contents</varname> in the final image</title>
+
+   <para>
+    Each path directly listed in <varname>contents</varname> will have a symlink in the root of the image.
+   </para>
+
+   <para>
+    For example:
+<programlisting><![CDATA[
+pkgs.dockerTools.buildLayeredImage {
+  name = "hello";
+  contents = [ pkgs.hello ];
+}
+]]></programlisting>
+    will create symlinks for all the paths in the <literal>hello</literal> package:
+<screen><![CDATA[
+/bin/hello -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/bin/hello
+/share/info/hello.info -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/share/info/hello.info
+/share/locale/bg/LC_MESSAGES/hello.mo -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/share/locale/bg/LC_MESSAGES/hello.mo
+]]></screen>
+   </para>
+  </section>
+
+  <section xml:id="dockerTools-buildLayeredImage-arg-config">
+   <title>Automatic inclusion of <varname>config</varname> references</title>
+
+   <para>
+    The closure of <varname>config</varname> is automatically included in the closure of the final image.
+   </para>
+
+   <para>
+    This allows you to make very simple Docker images with very little code. This container will start up and run <command>hello</command>:
+<programlisting><![CDATA[
+pkgs.dockerTools.buildLayeredImage {
+  name = "hello";
+  config.Cmd = [ "${pkgs.hello}/bin/hello" ];
+}
+]]></programlisting>
+   </para>
+  </section>
+
+  <section xml:id="dockerTools-buildLayeredImage-arg-maxLayers">
+   <title>Adjusting <varname>maxLayers</varname></title>
+
+   <para>
+    Increasing the <varname>maxLayers</varname> increases the number of layers which have a chance to be shared between different images.
+   </para>
+
+   <para>
+    Modern Docker installations support up to 128 layers, however older versions support as few as 42.
+   </para>
+
+   <para>
+    If the produced image will not be extended by other Docker builds, it is safe to set <varname>maxLayers</varname> to <literal>128</literal>. However it will be impossible to extend the image further.
+   </para>
+
+   <para>
+    The first (<literal>maxLayers-2</literal>) most "popular" paths will have their own individual layers, then layer #<literal>maxLayers-1</literal> will contain all the remaining "unpopular" paths, and finally layer #<literal>maxLayers</literal> will contain the Image configuration.
+   </para>
+
+   <para>
+    Docker's Layers are not inherently ordered, they are content-addressable and are not explicitly layered until they are composed in to an Image.
+   </para>
+  </section>
+ </section>
+
+ <section xml:id="ssec-pkgs-dockerTools-fetchFromRegistry">
+  <title>pullImage</title>
+
+  <para>
+   This function is analogous to the <command>docker pull</command> command, in that it can be used to pull a Docker image from a Docker registry. By default <link xlink:href="https://hub.docker.com/">Docker Hub</link> is used to pull images.
+  </para>
+
+  <para>
+   Its parameters are described in the example below:
+  </para>
+
+  <example xml:id='ex-dockerTools-pullImage'>
+   <title>Docker pull</title>
+<programlisting>
+pullImage {
+  imageName = "nixos/nix"; <co xml:id='ex-dockerTools-pullImage-1' />
+  imageDigest = "sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b"; <co xml:id='ex-dockerTools-pullImage-2' />
+  finalImageName = "nix"; <co xml:id='ex-dockerTools-pullImage-3' />
+  finalImageTag = "1.11";  <co xml:id='ex-dockerTools-pullImage-4' />
+  sha256 = "0mqjy3zq2v6rrhizgb9nvhczl87lcfphq9601wcprdika2jz7qh8"; <co xml:id='ex-dockerTools-pullImage-5' />
+  os = "linux"; <co xml:id='ex-dockerTools-pullImage-6' />
+  arch = "x86_64"; <co xml:id='ex-dockerTools-pullImage-7' />
+}
+</programlisting>
+  </example>
+
+  <calloutlist>
+   <callout arearefs='ex-dockerTools-pullImage-1'>
+    <para>
+     <varname>imageName</varname> specifies the name of the image to be downloaded, which can also include the registry namespace (e.g. <literal>nixos</literal>). This argument is required.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-2'>
+    <para>
+     <varname>imageDigest</varname> specifies the digest of the image to be downloaded. This argument is required.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-3'>
+    <para>
+     <varname>finalImageName</varname>, if specified, this is the name of the image to be created. Note it is never used to fetch the image since we prefer to rely on the immutable digest ID. By default it's equal to <varname>imageName</varname>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-4'>
+    <para>
+     <varname>finalImageTag</varname>, if specified, this is the tag of the image to be created. Note it is never used to fetch the image since we prefer to rely on the immutable digest ID. By default it's <literal>latest</literal>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-5'>
+    <para>
+     <varname>sha256</varname> is the checksum of the whole fetched image. This argument is required.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-6'>
+    <para>
+     <varname>os</varname>, if specified, is the operating system of the fetched image. By default it's <literal>linux</literal>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-7'>
+    <para>
+     <varname>arch</varname>, if specified, is the cpu architecture of the fetched image. By default it's <literal>x86_64</literal>.
+    </para>
+   </callout>
+  </calloutlist>
+
+  <para>
+   <literal>nix-prefetch-docker</literal> command can be used to get required image parameters:
+<screen>
+<prompt>$ </prompt>nix run nixpkgs.nix-prefetch-docker -c nix-prefetch-docker --image-name mysql --image-tag 5
+</screen>
+   Since a given <varname>imageName</varname> may transparently refer to a manifest list of images which support multiple architectures and/or operating systems, you can supply the <option>--os</option> and <option>--arch</option> arguments to specify exactly which image you want. By default it will match the OS and architecture of the host the command is run on.
+<screen>
+<prompt>$ </prompt>nix-prefetch-docker --image-name mysql --image-tag 5 --arch x86_64 --os linux
+</screen>
+   Desired image name and tag can be set using <option>--final-image-name</option> and <option>--final-image-tag</option> arguments:
+<screen>
+<prompt>$ </prompt>nix-prefetch-docker --image-name mysql --image-tag 5 --final-image-name eu.gcr.io/my-project/mysql --final-image-tag prod
+</screen>
+  </para>
+ </section>
+
+ <section xml:id="ssec-pkgs-dockerTools-exportImage">
+  <title>exportImage</title>
+
+  <para>
+   This function is analogous to the <command>docker export</command> command, in that it can be used to flatten a Docker image that contains multiple layers. It is in fact the result of the merge of all the layers of the image. As such, the result is suitable for being imported in Docker with <command>docker import</command>.
+  </para>
+
+  <note>
+   <para>
+    Using this function requires the <literal>kvm</literal> device to be available.
+   </para>
+  </note>
+
+  <para>
+   The parameters of <varname>exportImage</varname> are the following:
+  </para>
+
+  <example xml:id='ex-dockerTools-exportImage'>
+   <title>Docker export</title>
+<programlisting>
+exportImage {
+  fromImage = someLayeredImage;
+  fromImageName = null;
+  fromImageTag = null;
+
+  name = someLayeredImage.name;
+}
+</programlisting>
+  </example>
+
+  <para>
+   The parameters relative to the base image have the same synopsis as described in <xref linkend='ssec-pkgs-dockerTools-buildImage'/>, except that <varname>fromImage</varname> is the only required argument in this case.
+  </para>
+
+  <para>
+   The <varname>name</varname> argument is the name of the derivation output, which defaults to <varname>fromImage.name</varname>.
+  </para>
+ </section>
+
+ <section xml:id="ssec-pkgs-dockerTools-shadowSetup">
+  <title>shadowSetup</title>
+
+  <para>
+   This constant string is a helper for setting up the base files for managing users and groups, only if such files don't exist already. It is suitable for being used in a <varname>runAsRoot</varname> <xref linkend='ex-dockerTools-buildImage-runAsRoot'/> script for cases like in the example below:
+  </para>
+
+  <example xml:id='ex-dockerTools-shadowSetup'>
+   <title>Shadow base files</title>
+<programlisting>
+buildImage {
+  name = "shadow-basic";
+
+  runAsRoot = ''
+    #!${pkgs.runtimeShell}
+    ${shadowSetup}
+    groupadd -r redis
+    useradd -r -g redis redis
+    mkdir /data
+    chown redis:redis /data
+  '';
+}
+</programlisting>
+  </example>
+
+  <para>
+   Creating base files like <literal>/etc/passwd</literal> or <literal>/etc/login.defs</literal> is necessary for shadow-utils to manipulate users and groups.
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/images/ocitools.xml

@@ -0,0 +1,62 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-pkgs-ociTools">
+ <title>pkgs.ociTools</title>
+
+ <para>
+  <varname>pkgs.ociTools</varname> is a set of functions for creating containers according to the <link xlink:href="https://github.com/opencontainers/runtime-spec">OCI container specification v1.0.0</link>. Beyond that it makes no assumptions about the container runner you choose to use to run the created container.
+ </para>
+
+ <section xml:id="ssec-pkgs-ociTools-buildContainer">
+  <title>buildContainer</title>
+
+  <para>
+   This function creates a simple OCI container that runs a single command inside of it. An OCI container consists of a <varname>config.json</varname> and a rootfs directory.The nix store of the container will contain all referenced dependencies of the given command.
+  </para>
+
+  <para>
+   The parameters of <varname>buildContainer</varname> with an example value are described below:
+  </para>
+
+  <example xml:id='ex-ociTools-buildContainer'>
+   <title>Build Container</title>
+<programlisting>
+buildContainer {
+  args = [ (with pkgs; writeScript "run.sh" ''
+    #!${bash}/bin/bash
+    exec ${bash}/bin/bash
+  '').outPath ]; <co xml:id='ex-ociTools-buildContainer-1' />
+
+  mounts = {
+    "/data" = {
+      type = "none";
+      source = "/var/lib/mydata";
+      options = [ "bind" ];
+    };
+  };<co xml:id='ex-ociTools-buildContainer-2' />
+
+  readonly = false; <co xml:id='ex-ociTools-buildContainer-3' />
+}
+
+    </programlisting>
+   <calloutlist>
+    <callout arearefs='ex-ociTools-buildContainer-1'>
+     <para>
+      <varname>args</varname> specifies a set of arguments to run inside the container. This is the only required argument for <varname>buildContainer</varname>. All referenced packages inside the derivation will be made available inside the container
+     </para>
+    </callout>
+    <callout arearefs='ex-ociTools-buildContainer-2'>
+     <para>
+      <varname>mounts</varname> specifies additional mount points chosen by the user. By default only a minimal set of necessary filesystems are mounted into the container (e.g procfs, cgroupfs)
+     </para>
+    </callout>
+    <callout arearefs='ex-ociTools-buildContainer-3'>
+     <para>
+      <varname>readonly</varname> makes the container's rootfs read-only if it is set to true. The default value is false <literal>false</literal>.
+     </para>
+    </callout>
+   </calloutlist>
+  </example>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/images/snap/example-firefox.nix

@@ -0,0 +1,28 @@
+let
+  inherit (import <nixpkgs> { }) snapTools firefox;
+in snapTools.makeSnap {
+  meta = {
+    name = "nix-example-firefox";
+    summary = firefox.meta.description;
+    architectures = [ "amd64" ];
+    apps.nix-example-firefox = {
+      command = "${firefox}/bin/firefox";
+      plugs = [
+        "pulseaudio"
+        "camera"
+        "browser-support"
+        "avahi-observe"
+        "cups-control"
+        "desktop"
+        "desktop-legacy"
+        "gsettings"
+        "home"
+        "network"
+        "mount-observe"
+        "removable-media"
+        "x11"
+      ];
+    };
+    confinement = "strict";
+  };
+}

third_party/nixpkgs/doc/builders/images/snap/example-hello.nix

@@ -0,0 +1,12 @@
+let
+  inherit (import <nixpkgs> { }) snapTools hello;
+in snapTools.makeSnap {
+  meta = {
+    name = "hello";
+    summary = hello.meta.description;
+    description = hello.meta.longDescription;
+    architectures = [ "amd64" ];
+    confinement = "strict";
+    apps.hello.command = "${hello}/bin/hello";
+  };
+}

third_party/nixpkgs/doc/builders/images/snaptools.xml

@@ -0,0 +1,59 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-pkgs-snapTools">
+ <title>pkgs.snapTools</title>
+
+ <para>
+  <varname>pkgs.snapTools</varname> is a set of functions for creating Snapcraft images. Snap and Snapcraft is not used to perform these operations.
+ </para>
+
+ <section xml:id="ssec-pkgs-snapTools-makeSnap-signature">
+  <title>The makeSnap Function</title>
+
+  <para>
+   <function>makeSnap</function> takes a single named argument, <parameter>meta</parameter>. This argument mirrors <link xlink:href="https://docs.snapcraft.io/snap-format">the upstream <filename>snap.yaml</filename> format</link> exactly.
+  </para>
+
+  <para>
+   The <parameter>base</parameter> should not be be specified, as <function>makeSnap</function> will force set it.
+  </para>
+
+  <para>
+   Currently, <function>makeSnap</function> does not support creating GUI stubs.
+  </para>
+ </section>
+
+ <section xml:id="ssec-pkgs-snapTools-build-a-snap-hello">
+  <title>Build a Hello World Snap</title>
+
+  <example xml:id="ex-snapTools-buildSnap-hello">
+   <title>Making a Hello World Snap</title>
+   <para>
+    The following expression packages GNU Hello as a Snapcraft snap.
+   </para>
+<programlisting><xi:include href="./snap/example-hello.nix" parse="text" /></programlisting>
+   <para>
+    <command>nix-build</command> this expression and install it with <command>snap install ./result --dangerous</command>. <command>hello</command> will now be the Snapcraft version of the package.
+   </para>
+  </example>
+ </section>
+
+ <section xml:id="ssec-pkgs-snapTools-build-a-snap-firefox">
+  <title>Build a Hello World Snap</title>
+
+  <example xml:id="ex-snapTools-buildSnap-firefox">
+   <title>Making a Graphical Snap</title>
+   <para>
+    Graphical programs require many more integrations with the host. This example uses Firefox as an example, because it is one of the most complicated programs we could package.
+   </para>
+<programlisting><xi:include href="./snap/example-firefox.nix" parse="text" /></programlisting>
+   <para>
+    <command>nix-build</command> this expression and install it with <command>snap install ./result --dangerous</command>. <command>nix-example-firefox</command> will now be the Snapcraft version of the Firefox package.
+   </para>
+   <para>
+    The specific meaning behind plugs can be looked up in the <link xlink:href="https://docs.snapcraft.io/supported-interfaces">Snapcraft interface documentation</link>.
+   </para>
+  </example>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/packages/citrix.xml

@@ -0,0 +1,44 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-citrix">
+ <title>Citrix Workspace</title>
+
+ <para>
+  <note>
+   <para>
+    Please note that the <literal>citrix_receiver</literal> package has been deprecated since its development was <link xlink:href="https://docs.citrix.com/en-us/citrix-workspace-app.html">discontinued by upstream</link> and has been replaced by <link xlink:href="https://www.citrix.com/products/workspace-app/">the citrix workspace app</link>.
+   </para>
+  </note>
+  <link xlink:href="https://www.citrix.com/products/receiver/">Citrix Receiver</link> and <link xlink:href="https://www.citrix.com/products/workspace-app/">Citrix Workspace App</link> are a remote desktop viewers which provide access to <link xlink:href="https://www.citrix.com/products/xenapp-xendesktop/">XenDesktop</link> installations.
+ </para>
+
+ <section xml:id="sec-citrix-base">
+  <title>Basic usage</title>
+
+  <para>
+   The tarball archive needs to be downloaded manually as the license agreements of the vendor for <link xlink:href="https://www.citrix.com/downloads/citrix-receiver/">Citrix Receiver</link> or <link xlink:href="https://www.citrix.de/downloads/workspace-app/linux/workspace-app-for-linux-latest.html">Citrix Workspace</link> need to be accepted first. Then run <command>nix-prefetch-url file://$PWD/linuxx64-$version.tar.gz</command>. With the archive available in the store the package can be built and installed with Nix.
+  </para>
+
+  <warning>
+   <title>Caution with <command>nix-shell</command> installs</title>
+   <para>
+    It's recommended to install <literal>Citrix Receiver</literal> and/or <literal>Citrix Workspace</literal> using <literal>nix-env -i</literal> or globally to ensure that the <literal>.desktop</literal> files are installed properly into <literal>$XDG_CONFIG_DIRS</literal>. Otherwise it won't be possible to open <literal>.ica</literal> files automatically from the browser to start a Citrix connection.
+   </para>
+  </warning>
+ </section>
+
+ <section xml:id="sec-citrix-custom-certs">
+  <title>Custom certificates</title>
+
+  <para>
+   The <literal>Citrix Workspace App</literal> in <literal>nixpkgs</literal> trust several certificates <link xlink:href="https://curl.haxx.se/docs/caextract.html">from the Mozilla database</link> by default. However several companies using Citrix might require their own corporate certificate. On distros with imperative packaging these certs can be stored easily in <link xlink:href="https://developer-docs.citrix.com/projects/receiver-for-linux-command-reference/en/13.7/"><literal>$ICAROOT</literal></link>, however this directory is a store path in <literal>nixpkgs</literal>. In order to work around this issue the package provides a simple mechanism to add custom certificates without rebuilding the entire package using <literal>symlinkJoin</literal>:
+<programlisting>
+<![CDATA[with import <nixpkgs> { config.allowUnfree = true; };
+let extraCerts = [ ./custom-cert-1.pem ./custom-cert-2.pem /* ... */ ]; in
+citrix_workspace.override {
+  inherit extraCerts;
+}]]>
+</programlisting>
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/packages/dlib.xml

@@ -0,0 +1,24 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="dlib">
+ <title>DLib</title>
+
+ <para>
+  <link xlink:href="http://dlib.net/">DLib</link> is a modern, C++-based toolkit which provides several machine learning algorithms.
+ </para>
+
+ <section xml:id="compiling-without-avx-support">
+  <title>Compiling without AVX support</title>
+
+  <para>
+   Especially older CPUs don't support <link xlink:href="https://en.wikipedia.org/wiki/Advanced_Vector_Extensions">AVX</link> (<abbrev>Advanced Vector Extensions</abbrev>) instructions that are used by DLib to optimize their algorithms.
+  </para>
+
+  <para>
+   On the affected hardware errors like <literal>Illegal instruction</literal> will occur. In those cases AVX support needs to be disabled:
+<programlisting>self: super: {
+  dlib = super.dlib.override { avxSupport = false; };
+}</programlisting>
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/packages/eclipse.xml

@@ -0,0 +1,72 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-eclipse">
+ <title>Eclipse</title>
+
+ <para>
+  The Nix expressions related to the Eclipse platform and IDE are in <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/eclipse"><filename>pkgs/applications/editors/eclipse</filename></link>.
+ </para>
+
+ <para>
+  Nixpkgs provides a number of packages that will install Eclipse in its various forms. These range from the bare-bones Eclipse Platform to the more fully featured Eclipse SDK or Scala-IDE packages and multiple version are often available. It is possible to list available Eclipse packages by issuing the command:
+<screen>
+<prompt>$ </prompt>nix-env -f '&lt;nixpkgs&gt;' -qaP -A eclipses --description
+</screen>
+  Once an Eclipse variant is installed it can be run using the <command>eclipse</command> command, as expected. From within Eclipse it is then possible to install plugins in the usual manner by either manually specifying an Eclipse update site or by installing the Marketplace Client plugin and using it to discover and install other plugins. This installation method provides an Eclipse installation that closely resemble a manually installed Eclipse.
+ </para>
+
+ <para>
+  If you prefer to install plugins in a more declarative manner then Nixpkgs also offer a number of Eclipse plugins that can be installed in an <emphasis>Eclipse environment</emphasis>. This type of environment is created using the function <varname>eclipseWithPlugins</varname> found inside the <varname>nixpkgs.eclipses</varname> attribute set. This function takes as argument <literal>{ eclipse, plugins ? [], jvmArgs ? [] }</literal> where <varname>eclipse</varname> is a one of the Eclipse packages described above, <varname>plugins</varname> is a list of plugin derivations, and <varname>jvmArgs</varname> is a list of arguments given to the JVM running the Eclipse. For example, say you wish to install the latest Eclipse Platform with the popular Eclipse Color Theme plugin and also allow Eclipse to use more RAM. You could then add
+<screen>
+packageOverrides = pkgs: {
+  myEclipse = with pkgs.eclipses; eclipseWithPlugins {
+    eclipse = eclipse-platform;
+    jvmArgs = [ "-Xmx2048m" ];
+    plugins = [ plugins.color-theme ];
+  };
+}
+</screen>
+  to your Nixpkgs configuration (<filename>~/.config/nixpkgs/config.nix</filename>) and install it by running <command>nix-env -f '&lt;nixpkgs&gt;' -iA myEclipse</command> and afterward run Eclipse as usual. It is possible to find out which plugins are available for installation using <varname>eclipseWithPlugins</varname> by running
+<screen>
+<prompt>$ </prompt>nix-env -f '&lt;nixpkgs&gt;' -qaP -A eclipses.plugins --description
+</screen>
+ </para>
+
+ <para>
+  If there is a need to install plugins that are not available in Nixpkgs then it may be possible to define these plugins outside Nixpkgs using the <varname>buildEclipseUpdateSite</varname> and <varname>buildEclipsePlugin</varname> functions found in the <varname>nixpkgs.eclipses.plugins</varname> attribute set. Use the <varname>buildEclipseUpdateSite</varname> function to install a plugin distributed as an Eclipse update site. This function takes <literal>{ name, src }</literal> as argument where <literal>src</literal> indicates the Eclipse update site archive. All Eclipse features and plugins within the downloaded update site will be installed. When an update site archive is not available then the <varname>buildEclipsePlugin</varname> function can be used to install a plugin that consists of a pair of feature and plugin JARs. This function takes an argument <literal>{ name, srcFeature, srcPlugin }</literal> where <literal>srcFeature</literal> and <literal>srcPlugin</literal> are the feature and plugin JARs, respectively.
+ </para>
+
+ <para>
+  Expanding the previous example with two plugins using the above functions we have
+<screen>
+packageOverrides = pkgs: {
+  myEclipse = with pkgs.eclipses; eclipseWithPlugins {
+    eclipse = eclipse-platform;
+    jvmArgs = [ "-Xmx2048m" ];
+    plugins = [
+      plugins.color-theme
+      (plugins.buildEclipsePlugin {
+        name = "myplugin1-1.0";
+        srcFeature = fetchurl {
+          url = "http://…/features/myplugin1.jar";
+          sha256 = "123…";
+        };
+        srcPlugin = fetchurl {
+          url = "http://…/plugins/myplugin1.jar";
+          sha256 = "123…";
+        };
+      });
+      (plugins.buildEclipseUpdateSite {
+        name = "myplugin2-1.0";
+        src = fetchurl {
+          stripRoot = false;
+          url = "http://…/myplugin2.zip";
+          sha256 = "123…";
+        };
+      });
+    ];
+  };
+}
+</screen>
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/elm.xml

@@ -0,0 +1,17 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-elm">
+ <title>Elm</title>
+
+ <para>
+  To start a development environment do <command>nix-shell -p elmPackages.elm elmPackages.elm-format</command>
+ </para>
+
+ <para>
+  To update Elm compiler, see <filename>nixpkgs/pkgs/development/compilers/elm/README.md</filename>.
+ </para>
+
+ <para>
+  To package Elm applications, <link xlink:href="https://github.com/hercules-ci/elm2nix#elm2nix">read about elm2nix</link>.
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/emacs.xml

@@ -0,0 +1,131 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-emacs">
+ <title>Emacs</title>
+
+ <section xml:id="sec-emacs-config">
+  <title>Configuring Emacs</title>
+
+  <para>
+   The Emacs package comes with some extra helpers to make it easier to configure. <varname>emacsWithPackages</varname> allows you to manage packages from ELPA. This means that you will not have to install that packages from within Emacs. For instance, if you wanted to use <literal>company</literal>, <literal>counsel</literal>, <literal>flycheck</literal>, <literal>ivy</literal>, <literal>magit</literal>, <literal>projectile</literal>, and <literal>use-package</literal> you could use this as a <filename>~/.config/nixpkgs/config.nix</filename> override:
+  </para>
+
+<screen>
+{
+  packageOverrides = pkgs: with pkgs; {
+    myEmacs = emacsWithPackages (epkgs: (with epkgs.melpaStablePackages; [
+      company
+      counsel
+      flycheck
+      ivy
+      magit
+      projectile
+      use-package
+    ]));
+  }
+}
+</screen>
+
+  <para>
+   You can install it like any other packages via <command>nix-env -iA myEmacs</command>. However, this will only install those packages. It will not <literal>configure</literal> them for us. To do this, we need to provide a configuration file. Luckily, it is possible to do this from within Nix! By modifying the above example, we can make Emacs load a custom config file. The key is to create a package that provide a <filename>default.el</filename> file in <filename>/share/emacs/site-start/</filename>. Emacs knows to load this file automatically when it starts.
+  </para>
+
+<screen>
+{
+  packageOverrides = pkgs: with pkgs; rec {
+    myEmacsConfig = writeText "default.el" ''
+;; initialize package
+
+(require 'package)
+(package-initialize 'noactivate)
+(eval-when-compile
+  (require 'use-package))
+
+;; load some packages
+
+(use-package company
+  :bind ("&lt;C-tab&gt;" . company-complete)
+  :diminish company-mode
+  :commands (company-mode global-company-mode)
+  :defer 1
+  :config
+  (global-company-mode))
+
+(use-package counsel
+  :commands (counsel-descbinds)
+  :bind (([remap execute-extended-command] . counsel-M-x)
+         ("C-x C-f" . counsel-find-file)
+         ("C-c g" . counsel-git)
+         ("C-c j" . counsel-git-grep)
+         ("C-c k" . counsel-ag)
+         ("C-x l" . counsel-locate)
+         ("M-y" . counsel-yank-pop)))
+
+(use-package flycheck
+  :defer 2
+  :config (global-flycheck-mode))
+
+(use-package ivy
+  :defer 1
+  :bind (("C-c C-r" . ivy-resume)
+         ("C-x C-b" . ivy-switch-buffer)
+         :map ivy-minibuffer-map
+         ("C-j" . ivy-call))
+  :diminish ivy-mode
+  :commands ivy-mode
+  :config
+  (ivy-mode 1))
+
+(use-package magit
+  :defer
+  :if (executable-find "git")
+  :bind (("C-x g" . magit-status)
+         ("C-x G" . magit-dispatch-popup))
+  :init
+  (setq magit-completing-read-function 'ivy-completing-read))
+
+(use-package projectile
+  :commands projectile-mode
+  :bind-keymap ("C-c p" . projectile-command-map)
+  :defer 5
+  :config
+  (projectile-global-mode))
+    '';
+    myEmacs = emacsWithPackages (epkgs: (with epkgs.melpaStablePackages; [
+      (runCommand "default.el" {} ''
+mkdir -p $out/share/emacs/site-lisp
+cp ${myEmacsConfig} $out/share/emacs/site-lisp/default.el
+'')
+      company
+      counsel
+      flycheck
+      ivy
+      magit
+      projectile
+      use-package
+    ]));
+  };
+}
+</screen>
+
+  <para>
+   This provides a fairly full Emacs start file. It will load in addition to the user's presonal config. You can always disable it by passing <command>-q</command> to the Emacs command.
+  </para>
+
+  <para>
+   Sometimes <varname>emacsWithPackages</varname> is not enough, as this package set has some priorities imposed on packages (with the lowest priority assigned to Melpa Unstable, and the highest for packages manually defined in <filename>pkgs/top-level/emacs-packages.nix</filename>). But you can't control this priorities when some package is installed as a dependency. You can override it on per-package-basis, providing all the required dependencies manually - but it's tedious and there is always a possibility that an unwanted dependency will sneak in through some other package. To completely override such a package you can use <varname>overrideScope'</varname>.
+  </para>
+
+<screen>
+overrides = self: super: rec {
+  haskell-mode = self.melpaPackages.haskell-mode;
+  ...
+};
+((emacsPackagesGen emacs).overrideScope' overrides).emacsWithPackages (p: with p; [
+  # here both these package will use haskell-mode of our own choice
+  ghc-mod
+  dante
+])
+</screen>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/packages/ibus.xml

@@ -0,0 +1,57 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-ibus-typing-booster">
+ <title>ibus-engines.typing-booster</title>
+
+ <para>
+  This package is an ibus-based completion method to speed up typing.
+ </para>
+
+ <section xml:id="sec-ibus-typing-booster-activate">
+  <title>Activating the engine</title>
+
+  <para>
+   IBus needs to be configured accordingly to activate <literal>typing-booster</literal>. The configuration depends on the desktop manager in use. For detailed instructions, please refer to the <link xlink:href="https://mike-fabian.github.io/ibus-typing-booster/documentation.html">upstream docs</link>.
+  </para>
+
+  <para>
+   On NixOS you need to explicitly enable <literal>ibus</literal> with given engines before customizing your desktop to use <literal>typing-booster</literal>. This can be achieved using the <literal>ibus</literal> module:
+<programlisting>{ pkgs, ... }: {
+  i18n.inputMethod = {
+    enabled = "ibus";
+    ibus.engines = with pkgs.ibus-engines; [ typing-booster ];
+  };
+}</programlisting>
+  </para>
+ </section>
+
+ <section xml:id="sec-ibus-typing-booster-customize-hunspell">
+  <title>Using custom hunspell dictionaries</title>
+
+  <para>
+   The IBus engine is based on <literal>hunspell</literal> to support completion in many languages. By default the dictionaries <literal>de-de</literal>, <literal>en-us</literal>, <literal>fr-moderne</literal> <literal>es-es</literal>, <literal>it-it</literal>, <literal>sv-se</literal> and <literal>sv-fi</literal> are in use. To add another dictionary, the package can be overridden like this:
+<programlisting>ibus-engines.typing-booster.override {
+  langs = [ "de-at" "en-gb" ];
+}</programlisting>
+  </para>
+
+  <para>
+   <emphasis>Note: each language passed to <literal>langs</literal> must be an attribute name in <literal>pkgs.hunspellDicts</literal>.</emphasis>
+  </para>
+ </section>
+
+ <section xml:id="sec-ibus-typing-booster-emoji-picker">
+  <title>Built-in emoji picker</title>
+
+  <para>
+   The <literal>ibus-engines.typing-booster</literal> package contains a program named <literal>emoji-picker</literal>. To display all emojis correctly, a special font such as <literal>noto-fonts-emoji</literal> is needed:
+  </para>
+
+  <para>
+   On NixOS it can be installed using the following expression:
+<programlisting>{ pkgs, ... }: {
+  fonts.fonts = with pkgs; [ noto-fonts-emoji ];
+}</programlisting>
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/packages/index.xml

@@ -0,0 +1,24 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-packages">
+ <title>Packages</title>
+ <para>
+  This chapter contains information about how to use and maintain the Nix expressions for a number of specific packages, such as the Linux kernel or X.org.
+ </para>
+ <xi:include href="citrix.xml" />
+ <xi:include href="dlib.xml" />
+ <xi:include href="eclipse.xml" />
+ <xi:include href="elm.xml" />
+ <xi:include href="emacs.xml" />
+ <xi:include href="ibus.xml" />
+ <xi:include href="kakoune.xml" />
+ <xi:include href="linux.xml" />
+ <xi:include href="locales.xml" />
+ <xi:include href="nginx.xml" />
+ <xi:include href="opengl.xml" />
+ <xi:include href="shell-helpers.xml" />
+ <xi:include href="steam.xml" />
+ <xi:include href="urxvt.xml" />
+ <xi:include href="weechat.xml" />
+ <xi:include href="xorg.xml" />
+</chapter>

third_party/nixpkgs/doc/builders/packages/kakoune.xml

@@ -0,0 +1,14 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-kakoune">
+ <title>Kakoune</title>
+
+ <para>
+  Kakoune can be built to autoload plugins:
+<programlisting>(kakoune.override {
+  configure = {
+    plugins = with pkgs.kakounePlugins; [ parinfer-rust ];
+  };
+})</programlisting>
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/linux.xml

@@ -0,0 +1,85 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-linux-kernel">
+ <title>Linux kernel</title>
+
+ <para>
+  The Nix expressions to build the Linux kernel are in <link
+xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/os-specific/linux/kernel"><filename>pkgs/os-specific/linux/kernel</filename></link>.
+ </para>
+
+ <para>
+  The function that builds the kernel has an argument <varname>kernelPatches</varname> which should be a list of <literal>{name, patch, extraConfig}</literal> attribute sets, where <varname>name</varname> is the name of the patch (which is included in the kernel’s <varname>meta.description</varname> attribute), <varname>patch</varname> is the patch itself (possibly compressed), and <varname>extraConfig</varname> (optional) is a string specifying extra options to be concatenated to the kernel configuration file (<filename>.config</filename>).
+ </para>
+
+ <para>
+  The kernel derivation exports an attribute <varname>features</varname> specifying whether optional functionality is or isn’t enabled. This is used in NixOS to implement kernel-specific behaviour. For instance, if the kernel has the <varname>iwlwifi</varname> feature (i.e. has built-in support for Intel wireless chipsets), then NixOS doesn’t have to build the external <varname>iwlwifi</varname> package:
+<programlisting>
+modulesTree = [kernel]
+  ++ pkgs.lib.optional (!kernel.features ? iwlwifi) kernelPackages.iwlwifi
+  ++ ...;
+</programlisting>
+ </para>
+
+ <para>
+  How to add a new (major) version of the Linux kernel to Nixpkgs:
+  <orderedlist>
+   <listitem>
+    <para>
+     Copy the old Nix expression (e.g. <filename>linux-2.6.21.nix</filename>) to the new one (e.g. <filename>linux-2.6.22.nix</filename>) and update it.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Add the new kernel to <filename>all-packages.nix</filename> (e.g., create an attribute <varname>kernel_2_6_22</varname>).
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Now we’re going to update the kernel configuration. First unpack the kernel. Then for each supported platform (<literal>i686</literal>, <literal>x86_64</literal>, <literal>uml</literal>) do the following:
+     <orderedlist>
+      <listitem>
+       <para>
+        Make an copy from the old config (e.g. <filename>config-2.6.21-i686-smp</filename>) to the new one (e.g. <filename>config-2.6.22-i686-smp</filename>).
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Copy the config file for this platform (e.g. <filename>config-2.6.22-i686-smp</filename>) to <filename>.config</filename> in the kernel source tree.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Run <literal>make oldconfig ARCH=<replaceable>{i386,x86_64,um}</replaceable></literal> and answer all questions. (For the uml configuration, also add <literal>SHELL=bash</literal>.) Make sure to keep the configuration consistent between platforms (i.e. don’t enable some feature on <literal>i686</literal> and disable it on <literal>x86_64</literal>).
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        If needed you can also run <literal>make menuconfig</literal>:
+<screen>
+<prompt>$ </prompt>nix-env -i ncurses
+<prompt>$ </prompt>export NIX_CFLAGS_LINK=-lncurses
+<prompt>$ </prompt>make menuconfig ARCH=<replaceable>arch</replaceable></screen>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Copy <filename>.config</filename> over the new config file (e.g. <filename>config-2.6.22-i686-smp</filename>).
+       </para>
+      </listitem>
+     </orderedlist>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Test building the kernel: <literal>nix-build -A kernel_2_6_22</literal>. If it compiles, ship it! For extra credit, try booting NixOS with it.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     It may be that the new kernel requires updating the external kernel modules and kernel-dependent packages listed in the <varname>linuxPackagesFor</varname> function in <filename>all-packages.nix</filename> (such as the NVIDIA drivers, AUFS, etc.). If the updated packages aren’t backwards compatible with older kernels, you may need to keep the older versions around.
+    </para>
+   </listitem>
+  </orderedlist>
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/locales.xml

@@ -0,0 +1,13 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="locales">
+ <title>Locales</title>
+
+ <para>
+  To allow simultaneous use of packages linked against different versions of <literal>glibc</literal> with different locale archive formats Nixpkgs patches <literal>glibc</literal> to rely on <literal>LOCALE_ARCHIVE</literal> environment variable.
+ </para>
+
+ <para>
+  On non-NixOS distributions this variable is obviously not set. This can cause regressions in language support or even crashes in some Nixpkgs-provided programs. The simplest way to mitigate this problem is exporting the <literal>LOCALE_ARCHIVE</literal> variable pointing to <literal>${glibcLocales}/lib/locale/locale-archive</literal>. The drawback (and the reason this is not the default) is the relatively large (a hundred MiB) size of the full set of locales. It is possible to build a custom set of locales by overriding parameters <literal>allLocales</literal> and <literal>locales</literal> of the package.
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/nginx.xml

@@ -0,0 +1,25 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-nginx">
+ <title>Nginx</title>
+
+ <para>
+  <link xlink:href="https://nginx.org/">Nginx</link> is a reverse proxy and lightweight webserver.
+ </para>
+
+ <section xml:id="sec-nginx-etag">
+  <title>ETags on static files served from the Nix store</title>
+
+  <para>
+   HTTP has a couple different mechanisms for caching to prevent clients from having to download the same content repeatedly if a resource has not changed since the last time it was requested. When nginx is used as a server for static files, it implements the caching mechanism based on the <link xlink:href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Last-Modified"><literal>Last-Modified</literal></link> response header automatically; unfortunately, it works by using filesystem timestamps to determine the value of the <literal>Last-Modified</literal> header. This doesn't give the desired behavior when the file is in the Nix store, because all file timestamps are set to 0 (for reasons related to build reproducibility).
+  </para>
+
+  <para>
+   Fortunately, HTTP supports an alternative (and more effective) caching mechanism: the <link xlink:href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag"><literal>ETag</literal></link> response header. The value of the <literal>ETag</literal> header specifies some identifier for the particular content that the server is sending (e.g. a hash). When a client makes a second request for the same resource, it sends that value back in an <literal>If-None-Match</literal> header. If the ETag value is unchanged, then the server does not need to resend the content.
+  </para>
+
+  <para>
+   As of NixOS 19.09, the nginx package in Nixpkgs is patched such that when nginx serves a file out of <filename>/nix/store</filename>, the hash in the store path is used as the <literal>ETag</literal> header in the HTTP response, thus providing proper caching functionality. This happens automatically; you do not need to do modify any configuration to get this behavior.
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/packages/opengl.xml

@@ -0,0 +1,9 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-opengl">
+ <title>OpenGL</title>
+
+ <para>
+  Packages that use OpenGL have NixOS desktop as their primary target. The current solution for loading the GPU-specific drivers is based on <literal>libglvnd</literal> and looks for the driver implementation in <literal>LD_LIBRARY_PATH</literal>. If you are using a non-NixOS GNU/Linux/X11 desktop with free software video drivers, consider launching OpenGL-dependent programs from Nixpkgs with Nixpkgs versions of <literal>libglvnd</literal> and <literal>mesa_drivers</literal> in <literal>LD_LIBRARY_PATH</literal>. For proprietary video drivers you might have luck with also adding the corresponding video driver package.
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/shell-helpers.xml

@@ -0,0 +1,25 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-shell-helpers">
+ <title>Interactive shell helpers</title>
+
+ <para>
+  Some packages provide the shell integration to be more useful. But unlike other systems, nix doesn't have a standard share directory location. This is why a bunch <command>PACKAGE-share</command> scripts are shipped that print the location of the corresponding shared folder. Current list of such packages is as following:
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>autojump</literal>: <command>autojump-share</command>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     <literal>fzf</literal>: <command>fzf-share</command>
+    </para>
+   </listitem>
+  </itemizedlist>
+  E.g. <literal>autojump</literal> can then used in the .bashrc like this:
+<screen>
+  source "$(autojump-share)/autojump.bash"
+</screen>
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/steam.xml

@@ -0,0 +1,131 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-steam">
+ <title>Steam</title>
+
+ <section xml:id="sec-steam-nix">
+  <title>Steam in Nix</title>
+
+  <para>
+   Steam is distributed as a <filename>.deb</filename> file, for now only as an i686 package (the amd64 package only has documentation). When unpacked, it has a script called <filename>steam</filename> that in Ubuntu (their target distro) would go to <filename>/usr/bin </filename>. When run for the first time, this script copies some files to the user's home, which include another script that is the ultimate responsible for launching the steam binary, which is also in $HOME.
+  </para>
+
+  <para>
+   Nix problems and constraints:
+   <itemizedlist>
+    <listitem>
+     <para>
+      We don't have <filename>/bin/bash</filename> and many scripts point there. Similarly for <filename>/usr/bin/python</filename> .
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      We don't have the dynamic loader in <filename>/lib </filename>.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      The <filename>steam.sh</filename> script in $HOME can not be patched, as it is checked and rewritten by steam.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      The steam binary cannot be patched, it's also checked.
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+
+  <para>
+   The current approach to deploy Steam in NixOS is composing a FHS-compatible chroot environment, as documented <link xlink:href="http://sandervanderburg.blogspot.nl/2013/09/composing-fhs-compatible-chroot.html">here</link>. This allows us to have binaries in the expected paths without disrupting the system, and to avoid patching them to work in a non FHS environment.
+  </para>
+ </section>
+
+ <section xml:id="sec-steam-play">
+  <title>How to play</title>
+
+  <para>
+   For 64-bit systems it's important to have
+<programlisting>hardware.opengl.driSupport32Bit = true;</programlisting>
+   in your <filename>/etc/nixos/configuration.nix</filename>. You'll also need
+<programlisting>hardware.pulseaudio.support32Bit = true;</programlisting>
+   if you are using PulseAudio - this will enable 32bit ALSA apps integration. To use the Steam controller or other Steam supported controllers such as the DualShock 4 or Nintendo Switch Pro, you need to add
+<programlisting>hardware.steam-hardware.enable = true;</programlisting>
+   to your configuration.
+  </para>
+ </section>
+
+ <section xml:id="sec-steam-troub">
+  <title>Troubleshooting</title>
+
+  <para>
+   <variablelist>
+    <varlistentry>
+     <term>
+      Steam fails to start. What do I do?
+     </term>
+     <listitem>
+      <para>
+       Try to run
+<programlisting>strace steam</programlisting>
+       to see what is causing steam to fail.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      Using the FOSS Radeon or nouveau (nvidia) drivers
+     </term>
+     <listitem>
+      <itemizedlist>
+       <listitem>
+        <para>
+         The <literal>newStdcpp</literal> parameter was removed since NixOS 17.09 and should not be needed anymore.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Steam ships statically linked with a version of libcrypto that conflics with the one dynamically loaded by radeonsi_dri.so. If you get the error
+<programlisting>steam.sh: line 713: 7842 Segmentation fault (core dumped)</programlisting>
+         have a look at <link xlink:href="https://github.com/NixOS/nixpkgs/pull/20269">this pull request</link>.
+        </para>
+       </listitem>
+      </itemizedlist>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      Java
+     </term>
+     <listitem>
+      <orderedlist>
+       <listitem>
+        <para>
+         There is no java in steam chrootenv by default. If you get a message like
+<programlisting>/home/foo/.local/share/Steam/SteamApps/common/towns/towns.sh: line 1: java: command not found</programlisting>
+         You need to add
+<programlisting> steam.override { withJava = true; };</programlisting>
+         to your configuration.
+        </para>
+       </listitem>
+      </orderedlist>
+     </listitem>
+    </varlistentry>
+   </variablelist>
+  </para>
+ </section>
+
+ <section xml:id="sec-steam-run">
+  <title>steam-run</title>
+
+  <para>
+   The FHS-compatible chroot used for steam can also be used to run other linux games that expect a FHS environment. To do it, add
+<programlisting>pkgs.(steam.override {
+          nativeOnly = true;
+          newStdcpp = true;
+        }).run</programlisting>
+   to your configuration, rebuild, and run the game with
+<programlisting>steam-run ./foo</programlisting>
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/packages/unfree.xml

@@ -0,0 +1,13 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="unfree-software">
+ <title>Unfree software</title>
+
+ <para>
+  All users of Nixpkgs are free software users, and many users (and developers) of Nixpkgs want to limit and tightly control their exposure to unfree software. At the same time, many users need (or want) to run some specific pieces of proprietary software. Nixpkgs includes some expressions for unfree software packages. By default unfree software cannot be installed and doesn’t show up in searches. To allow installing unfree software in a single Nix invocation one can export <literal>NIXPKGS_ALLOW_UNFREE=1</literal>. For a persistent solution, users can set <literal>allowUnfree</literal> in the Nixpkgs configuration.
+ </para>
+
+ <para>
+  Fine-grained control is possible by defining <literal>allowUnfreePredicate</literal> function in config; it takes the <literal>mkDerivation</literal> parameter attrset and returns <literal>true</literal> for unfree packages that should be allowed.
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/urxvt.xml

@@ -0,0 +1,101 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-urxvt">
+ <title>Urxvt</title>
+
+ <para>
+  Urxvt, also known as rxvt-unicode, is a highly customizable terminal emulator.
+ </para>
+
+ <section xml:id="sec-urxvt-conf">
+
+  <title>Configuring urxvt</title>
+
+  <para>
+   In <literal>nixpkgs</literal>, urxvt is provided by the package
+   <literal>rxvt-unicode</literal>. It can be configured to include your choice
+   of plugins, reducing its closure size from the default configuration which
+   includes all available plugins. To make use of this functionality, use an
+   overlay or directly install an expression that overrides its configuration,
+   such as
+   <programlisting>rxvt-unicode.override { configure = { availablePlugins, ... }: {
+    plugins = with availablePlugins; [ perls resize-font vtwheel ];
+  }
+}</programlisting>
+   If the <literal>configure</literal> function returns an attrset without the
+   <literal>plugins</literal> attribute, <literal>availablePlugins</literal>
+   will be used automatically.
+  </para>
+
+  <para>
+   In order to add plugins but also keep all default plugins installed, it is
+   possible to use the following method:
+   <programlisting>rxvt-unicode.override { configure = { availablePlugins, ... }: {
+     plugins = (builtins.attrValues availablePlugins) ++ [ custom-plugin ];
+   };
+}</programlisting>
+  </para>
+
+  <para>
+   To get a list of all the plugins available, open the Nix REPL and run
+   <programlisting>$ nix repl
+:l &lt;nixpkgs&gt;
+map (p: p.name) pkgs.rxvt-unicode.plugins
+   </programlisting>
+   Alternatively, if your shell is bash or zsh and have completion enabled,
+   simply type <literal>nixpkgs.rxvt-unicode.plugins.&lt;tab&gt;</literal>.
+  </para>
+
+  <para>
+    In addition to <literal>plugins</literal> the options
+    <literal>extraDeps</literal> and <literal>perlDeps</literal> can be used
+    to install extra packages.
+    <literal>extraDeps</literal> can be used, for example, to provide 
+    <literal>xsel</literal> (a clipboard manager) to the clipboard plugin,
+    without installing it globally:
+    <programlisting>rxvt-unicode.override { configure = { availablePlugins, ... }: {
+     pluginsDeps = [ xsel ];
+   }
+}</programlisting>
+
+    <literal>perlDeps</literal> is a handy way to provide Perl packages to
+    your custom plugins (in <literal>$HOME/.urxvt/ext</literal>). For example,
+    if you need <literal>AnyEvent</literal> you can do:
+    <programlisting>rxvt-unicode.override { configure = { availablePlugins, ... }: {
+     perlDeps = with perlPackages; [ AnyEvent ];
+   }
+}</programlisting>
+  </para>
+
+ </section>
+
+ <section xml:id="sec-urxvt-pkg">
+
+  <title>Packaging urxvt plugins</title>
+
+  <para>
+   Urxvt plugins resides in
+   <literal>pkgs/applications/misc/rxvt-unicode-plugins</literal>.
+   To add a new plugin create an expression in a subdirectory and add the
+   package to the set in
+   <literal>pkgs/applications/misc/rxvt-unicode-plugins/default.nix</literal>.
+  </para>
+
+  <para>
+   A plugin can be any kind of derivation, the only requirement is that it
+   should always install perl scripts in <literal>$out/lib/urxvt/perl</literal>.
+   Look for existing plugins for examples.
+  </para>
+
+  <para>
+   If the plugin is itself a perl package that needs to be imported from
+   other plugins or scripts, add the following passthrough:
+   <programlisting>passthru.perlPackages = [ "self" ];
+</programlisting>
+   This will make the urxvt wrapper pick up the dependency and set up the perl
+   path accordingly.
+  </para>
+
+ </section>
+
+</section>

third_party/nixpkgs/doc/builders/packages/weechat.xml

@@ -0,0 +1,85 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-weechat">
+ <title>Weechat</title>
+
+ <para>
+  Weechat can be configured to include your choice of plugins, reducing its closure size from the default configuration which includes all available plugins. To make use of this functionality, install an expression that overrides its configuration such as
+<programlisting>weechat.override {configure = {availablePlugins, ...}: {
+    plugins = with availablePlugins; [ python perl ];
+  }
+}</programlisting>
+  If the <literal>configure</literal> function returns an attrset without the <literal>plugins</literal> attribute, <literal>availablePlugins</literal> will be used automatically.
+ </para>
+
+ <para>
+  The plugins currently available are <literal>python</literal>, <literal>perl</literal>, <literal>ruby</literal>, <literal>guile</literal>, <literal>tcl</literal> and <literal>lua</literal>.
+ </para>
+
+ <para>
+  The python and perl plugins allows the addition of extra libraries. For instance, the <literal>inotify.py</literal> script in weechat-scripts requires D-Bus or libnotify, and the <literal>fish.py</literal> script requires pycrypto. To use these scripts, use the plugin's <literal>withPackages</literal> attribute:
+<programlisting>weechat.override { configure = {availablePlugins, ...}: {
+    plugins = with availablePlugins; [
+            (python.withPackages (ps: with ps; [ pycrypto python-dbus ]))
+        ];
+    };
+}
+</programlisting>
+ </para>
+
+ <para>
+  In order to also keep all default plugins installed, it is possible to use the following method:
+<programlisting>weechat.override { configure = { availablePlugins, ... }: {
+  plugins = builtins.attrValues (availablePlugins // {
+    python = availablePlugins.python.withPackages (ps: with ps; [ pycrypto python-dbus ]);
+  });
+}; }
+</programlisting>
+ </para>
+
+ <para>
+  WeeChat allows to set defaults on startup using the <literal>--run-command</literal>. The <literal>configure</literal> method can be used to pass commands to the program:
+<programlisting>weechat.override {
+  configure = { availablePlugins, ... }: {
+    init = ''
+      /set foo bar
+      /server add freenode chat.freenode.org
+    '';
+  };
+}</programlisting>
+  Further values can be added to the list of commands when running <literal>weechat --run-command "your-commands"</literal>.
+ </para>
+
+ <para>
+  Additionally it's possible to specify scripts to be loaded when starting <literal>weechat</literal>. These will be loaded before the commands from <literal>init</literal>:
+<programlisting>weechat.override {
+  configure = { availablePlugins, ... }: {
+    scripts = with pkgs.weechatScripts; [
+      weechat-xmpp weechat-matrix-bridge wee-slack
+    ];
+    init = ''
+      /set plugins.var.python.jabber.key "val"
+    '':
+  };
+}</programlisting>
+ </para>
+
+ <para>
+  In <literal>nixpkgs</literal> there's a subpackage which contains derivations for WeeChat scripts. Such derivations expect a <literal>passthru.scripts</literal> attribute which contains a list of all scripts inside the store path. Furthermore all scripts have to live in <literal>$out/share</literal>. An exemplary derivation looks like this:
+<programlisting>{ stdenv, fetchurl }:
+
+stdenv.mkDerivation {
+  name = "exemplary-weechat-script";
+  src = fetchurl {
+    url = "https://scripts.tld/your-scripts.tar.gz";
+    sha256 = "...";
+  };
+  passthru.scripts = [ "foo.py" "bar.lua" ];
+  installPhase = ''
+    mkdir $out/share
+    cp foo.py $out/share
+    cp bar.lua $out/share
+  '';
+}</programlisting>
+ </para>
+</section>

third_party/nixpkgs/doc/builders/packages/xorg.xml

@@ -0,0 +1,34 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-xorg">
+ <title>X.org</title>
+
+ <para>
+  The Nix expressions for the X.org packages reside in <filename>pkgs/servers/x11/xorg/default.nix</filename>. This file is automatically generated from lists of tarballs in an X.org release. As such it should not be modified directly; rather, you should modify the lists, the generator script or the file <filename>pkgs/servers/x11/xorg/overrides.nix</filename>, in which you can override or add to the derivations produced by the generator.
+ </para>
+
+ <para>
+  The generator is invoked as follows:
+<screen>
+<prompt>$ </prompt>cd pkgs/servers/x11/xorg
+<prompt>$ </prompt>cat tarballs-7.5.list extra.list old.list \
+  | perl ./generate-expr-from-tarballs.pl
+</screen>
+  For each of the tarballs in the <filename>.list</filename> files, the script downloads it, unpacks it, and searches its <filename>configure.ac</filename> and <filename>*.pc.in</filename> files for dependencies. This information is used to generate <filename>default.nix</filename>. The generator caches downloaded tarballs between runs. Pay close attention to the <literal>NOT FOUND: <replaceable>name</replaceable></literal> messages at the end of the run, since they may indicate missing dependencies. (Some might be optional dependencies, however.)
+ </para>
+
+ <para>
+  A file like <filename>tarballs-7.5.list</filename> contains all tarballs in a X.org release. It can be generated like this:
+<screen>
+<prompt>$ </prompt>export i="mirror://xorg/X11R7.4/src/everything/"
+<prompt>$ </prompt>cat $(PRINT_PATH=1 nix-prefetch-url $i | tail -n 1) \
+  | perl -e 'while (&lt;>) { if (/(href|HREF)="([^"]*.bz2)"/) { print "$ENV{'i'}$2\n"; }; }' \
+  | sort > tarballs-7.4.list
+</screen>
+  <filename>extra.list</filename> contains libraries that aren’t part of X.org proper, but are closely related to it, such as <literal>libxcb</literal>. <filename>old.list</filename> contains some packages that were removed from X.org, but are still needed by some people or by other packages (such as <varname>imake</varname>).
+ </para>
+
+ <para>
+  If the expression for a package requires derivation attributes that the generator cannot figure out automatically (say, <varname>patches</varname> or a <varname>postInstall</varname> hook), you should modify <filename>pkgs/servers/x11/xorg/overrides.nix</filename>.
+ </para>
+</section>

third_party/nixpkgs/doc/builders/special.xml

@@ -0,0 +1,10 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-special">
+ <title>Special builders</title>
+ <para>
+  This chapter describes several special builders.
+ </para>
+ <xi:include href="special/fhs-environments.xml" />
+ <xi:include href="special/mkshell.xml" />
+</chapter>

third_party/nixpkgs/doc/builders/special/fhs-environments.xml

@@ -0,0 +1,122 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-fhs-environments">
+ <title>buildFHSUserEnv</title>
+
+ <para>
+  <function>buildFHSUserEnv</function> provides a way to build and run FHS-compatible lightweight sandboxes. It creates an isolated root with bound <filename>/nix/store</filename>, so its footprint in terms of disk space needed is quite small. This allows one to run software which is hard or unfeasible to patch for NixOS -- 3rd-party source trees with FHS assumptions, games distributed as tarballs, software with integrity checking and/or external self-updated binaries. It uses Linux namespaces feature to create temporary lightweight environments which are destroyed after all child processes exit, without root user rights requirement. Accepted arguments are:
+ </para>
+
+ <variablelist>
+  <varlistentry>
+   <term>
+    <literal>name</literal>
+   </term>
+   <listitem>
+    <para>
+     Environment name.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>targetPkgs</literal>
+   </term>
+   <listitem>
+    <para>
+     Packages to be installed for the main host's architecture (i.e. x86_64 on x86_64 installations). Along with libraries binaries are also installed.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>multiPkgs</literal>
+   </term>
+   <listitem>
+    <para>
+     Packages to be installed for all architectures supported by a host (i.e. i686 and x86_64 on x86_64 installations). Only libraries are installed by default.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>extraBuildCommands</literal>
+   </term>
+   <listitem>
+    <para>
+     Additional commands to be executed for finalizing the directory structure.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>extraBuildCommandsMulti</literal>
+   </term>
+   <listitem>
+    <para>
+     Like <literal>extraBuildCommands</literal>, but executed only on multilib architectures.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>extraOutputsToInstall</literal>
+   </term>
+   <listitem>
+    <para>
+     Additional derivation outputs to be linked for both target and multi-architecture packages.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>extraInstallCommands</literal>
+   </term>
+   <listitem>
+    <para>
+     Additional commands to be executed for finalizing the derivation with runner script.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>runScript</literal>
+   </term>
+   <listitem>
+    <para>
+     A command that would be executed inside the sandbox and passed all the command line arguments. It defaults to <literal>bash</literal>.
+    </para>
+   </listitem>
+  </varlistentry>
+ </variablelist>
+
+ <para>
+  One can create a simple environment using a <literal>shell.nix</literal> like that:
+ </para>
+
+<programlisting><![CDATA[
+{ pkgs ? import <nixpkgs> {} }:
+
+(pkgs.buildFHSUserEnv {
+  name = "simple-x11-env";
+  targetPkgs = pkgs: (with pkgs;
+    [ udev
+      alsaLib
+    ]) ++ (with pkgs.xorg;
+    [ libX11
+      libXcursor
+      libXrandr
+    ]);
+  multiPkgs = pkgs: (with pkgs;
+    [ udev
+      alsaLib
+    ]);
+  runScript = "bash";
+}).env
+]]></programlisting>
+
+ <para>
+  Running <literal>nix-shell</literal> would then drop you into a shell with these libraries and binaries available. You can use this to run closed-source applications which expect FHS structure without hassles: simply change <literal>runScript</literal> to the application path, e.g. <filename>./bin/start.sh</filename> -- relative paths are supported.
+ </para>
+</section>

third_party/nixpkgs/doc/builders/special/mkshell.xml

@@ -0,0 +1,24 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-pkgs-mkShell">
+ <title>pkgs.mkShell</title>
+
+ <para>
+  <function>pkgs.mkShell</function> is a special kind of derivation that is only useful when using it combined with <command>nix-shell</command>. It will in fact fail to instantiate when invoked with <command>nix-build</command>.
+ </para>
+
+ <section xml:id="sec-pkgs-mkShell-usage">
+  <title>Usage</title>
+
+<programlisting><![CDATA[
+{ pkgs ? import <nixpkgs> {} }:
+pkgs.mkShell {
+  # this will make all the build inputs from hello and gnutar
+  # available to the shell environment
+  inputsFrom = with pkgs; [ hello gnutar ];
+  buildInputs = [ pkgs.gnumake ];
+}
+]]></programlisting>
+ </section>
+</section>

third_party/nixpkgs/doc/builders/trivial-builders.xml

@@ -0,0 +1,90 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-trivial-builders">
+ <title>Trivial builders</title>
+ <para>
+  Nixpkgs provides a couple of functions that help with building derivations. The most important one, <function>stdenv.mkDerivation</function>, has already been documented above. The following functions wrap <function>stdenv.mkDerivation</function>, making it easier to use in certain cases.
+ </para>
+ <variablelist>
+  <varlistentry xml:id="trivial-builder-runCommand">
+   <term>
+    <literal>runCommand</literal>
+   </term>
+   <listitem>
+    <para>
+     This takes three arguments, <literal>name</literal>, <literal>env</literal>, and <literal>buildCommand</literal>. <literal>name</literal> is just the name that Nix will append to the store path in the same way that <literal>stdenv.mkDerivation</literal> uses its <literal>name</literal> attribute. <literal>env</literal> is an attribute set specifying environment variables that will be set for this derivation. These attributes are then passed to the wrapped <literal>stdenv.mkDerivation</literal>. <literal>buildCommand</literal> specifies the commands that will be run to create this derivation. Note that you will need to create <literal>$out</literal> for Nix to register the command as successful.
+    </para>
+    <para>
+     An example of using <literal>runCommand</literal> is provided below.
+    </para>
+<programlisting>
+(import &lt;nixpkgs&gt; {}).runCommand "my-example" {} ''
+  echo My example command is running
+
+  mkdir $out
+
+  echo I can write data to the Nix store > $out/message
+
+  echo I can also run basic commands like:
+
+  echo ls
+  ls
+
+  echo whoami
+  whoami
+
+  echo date
+  date
+''
+</programlisting>
+   </listitem>
+  </varlistentry>
+  <varlistentry xml:id="trivial-builder-runCommandCC">
+   <term>
+    <literal>runCommandCC</literal>
+   </term>
+   <listitem>
+    <para>
+     This works just like <literal>runCommand</literal>. The only difference is that it also provides a C compiler in <literal>buildCommand</literal>’s environment. To minimize your dependencies, you should only use this if you are sure you will need a C compiler as part of running your command.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry xml:id="trivial-builder-runCommandLocal">
+   <term>
+    <literal>runCommandLocal</literal>
+   </term>
+   <listitem>
+    <para>
+     Variant of <literal>runCommand</literal> that forces the derivation to be built locally, it is not substituted. This is intended for very cheap commands (&lt;1s execution time). It saves on the network roundrip and can speed up a build.
+    </para>
+    <note><para>
+      This sets <link xlink:href="https://nixos.org/nix/manual/#adv-attr-allowSubstitutes"><literal>allowSubstitutes</literal> to <literal>false</literal></link>, so only use <literal>runCommandLocal</literal> if you are certain the user will always have a builder for the <literal>system</literal> of the derivation. This should be true for most trivial use cases (e.g. just copying some files to a different location or adding symlinks), because there the <literal>system</literal> is usually the same as <literal>builtins.currentSystem</literal>.
+    </para></note>
+   </listitem>
+  </varlistentry>
+  <varlistentry xml:id="trivial-builder-writeText">
+   <term>
+    <literal>writeTextFile</literal>, <literal>writeText</literal>, <literal>writeTextDir</literal>, <literal>writeScript</literal>, <literal>writeScriptBin</literal>
+   </term>
+   <listitem>
+    <para>
+     These functions write <literal>text</literal> to the Nix store. This is useful for creating scripts from Nix expressions. <literal>writeTextFile</literal> takes an attribute set and expects two arguments, <literal>name</literal> and <literal>text</literal>. <literal>name</literal> corresponds to the name used in the Nix store path. <literal>text</literal> will be the contents of the file. You can also set <literal>executable</literal> to true to make this file have the executable bit set.
+    </para>
+    <para>
+     Many more commands wrap <literal>writeTextFile</literal> including <literal>writeText</literal>, <literal>writeTextDir</literal>, <literal>writeScript</literal>, and <literal>writeScriptBin</literal>. These are convenience functions over <literal>writeTextFile</literal>.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry xml:id="trivial-builder-symlinkJoin">
+   <term>
+    <literal>symlinkJoin</literal>
+   </term>
+   <listitem>
+    <para>
+     This can be used to put many derivations into the same directory structure. It works by creating a new derivation and adding symlinks to each of the paths listed. It expects two arguments, <literal>name</literal>, and <literal>paths</literal>. <literal>name</literal> is the name used in the Nix store path for the created derivation. <literal>paths</literal> is a list of paths that will be symlinked. These paths can be to Nix store derivations or any other subdirectory contained within.
+    </para>
+   </listitem>
+  </varlistentry>
+ </variablelist>
+</chapter>

third_party/nixpkgs/doc/contributing/coding-conventions.xml

@@ -0,0 +1,924 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="chap-conventions">
+ <title>Coding conventions</title>
+ <section xml:id="sec-syntax">
+  <title>Syntax</title>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Use 2 spaces of indentation per indentation level in Nix expressions, 4 spaces in shell scripts.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Do not use tab characters, i.e. configure your editor to use soft tabs. For instance, use <literal>(setq-default indent-tabs-mode nil)</literal> in Emacs. Everybody has different tab settings so it’s asking for trouble.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Use <literal>lowerCamelCase</literal> for variable names, not <literal>UpperCamelCase</literal>. Note, this rule does not apply to package attribute names, which instead follow the rules in <xref linkend="sec-package-naming"/>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Function calls with attribute set arguments are written as
+<programlisting>
+foo {
+  arg = ...;
+}
+</programlisting>
+     not
+<programlisting>
+foo
+{
+  arg = ...;
+}
+</programlisting>
+     Also fine is
+<programlisting>
+foo { arg = ...; }
+</programlisting>
+     if it's a short call.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     In attribute sets or lists that span multiple lines, the attribute names or list elements should be aligned:
+<programlisting>
+# A long list.
+list = [
+  elem1
+  elem2
+  elem3
+];
+
+# A long attribute set.
+attrs = {
+  attr1 = short_expr;
+  attr2 =
+    if true then big_expr else big_expr;
+};
+
+# Combined
+listOfAttrs = [
+  {
+    attr1 = 3;
+    attr2 = "fff";
+  }
+  {
+    attr1 = 5;
+    attr2 = "ggg";
+  }
+];
+</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Short lists or attribute sets can be written on one line:
+<programlisting>
+# A short list.
+list = [ elem1 elem2 elem3 ];
+
+# A short set.
+attrs = { x = 1280; y = 1024; };
+</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Breaking in the middle of a function argument can give hard-to-read code, like
+<programlisting>
+someFunction { x = 1280;
+  y = 1024; } otherArg
+  yetAnotherArg
+</programlisting>
+     (especially if the argument is very large, spanning multiple lines).
+    </para>
+    <para>
+     Better:
+<programlisting>
+someFunction
+  { x = 1280; y = 1024; }
+  otherArg
+  yetAnotherArg
+</programlisting>
+     or
+<programlisting>
+let res = { x = 1280; y = 1024; };
+in someFunction res otherArg yetAnotherArg
+</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The bodies of functions, asserts, and withs are not indented to prevent a lot of superfluous indentation levels, i.e.
+<programlisting>
+{ arg1, arg2 }:
+assert system == "i686-linux";
+stdenv.mkDerivation { ...
+</programlisting>
+     not
+<programlisting>
+{ arg1, arg2 }:
+  assert system == "i686-linux";
+    stdenv.mkDerivation { ...
+</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Function formal arguments are written as:
+<programlisting>
+{ arg1, arg2, arg3 }:
+</programlisting>
+     but if they don't fit on one line they're written as:
+<programlisting>
+{ arg1, arg2, arg3
+, arg4, ...
+, # Some comment...
+  argN
+}:
+</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Functions should list their expected arguments as precisely as possible. That is, write
+<programlisting>
+{ stdenv, fetchurl, perl }: <replaceable>...</replaceable>
+</programlisting>
+     instead of
+<programlisting>
+args: with args; <replaceable>...</replaceable>
+</programlisting>
+     or
+<programlisting>
+{ stdenv, fetchurl, perl, ... }: <replaceable>...</replaceable>
+</programlisting>
+    </para>
+    <para>
+     For functions that are truly generic in the number of arguments (such as wrappers around <varname>mkDerivation</varname>) that have some required arguments, you should write them using an <literal>@</literal>-pattern:
+<programlisting>
+{ stdenv, doCoverageAnalysis ? false, ... } @ args:
+
+stdenv.mkDerivation (args // {
+  <replaceable>...</replaceable> if doCoverageAnalysis then "bla" else "" <replaceable>...</replaceable>
+})
+</programlisting>
+     instead of
+<programlisting>
+args:
+
+args.stdenv.mkDerivation (args // {
+  <replaceable>...</replaceable> if args ? doCoverageAnalysis &amp;&amp; args.doCoverageAnalysis then "bla" else "" <replaceable>...</replaceable>
+})
+</programlisting>
+    </para>
+   </listitem>
+  </itemizedlist>
+ </section>
+ <section xml:id="sec-package-naming">
+  <title>Package naming</title>
+
+  <para>
+   The key words <emphasis>must</emphasis>, <emphasis>must not</emphasis>, <emphasis>required</emphasis>, <emphasis>shall</emphasis>, <emphasis>shall not</emphasis>, <emphasis>should</emphasis>, <emphasis>should not</emphasis>, <emphasis>recommended</emphasis>, <emphasis>may</emphasis>, and <emphasis>optional</emphasis> in this section are to be interpreted as described in <link xlink:href="https://tools.ietf.org/html/rfc2119">RFC 2119</link>. Only <emphasis>emphasized</emphasis> words are to be interpreted in this way.
+  </para>
+
+  <para>
+   In Nixpkgs, there are generally three different names associated with a package:
+   <itemizedlist>
+    <listitem>
+     <para>
+      The <varname>name</varname> attribute of the derivation (excluding the version part). This is what most users see, in particular when using <command>nix-env</command>.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      The variable name used for the instantiated package in <filename>all-packages.nix</filename>, and when passing it as a dependency to other functions. Typically this is called the <emphasis>package attribute name</emphasis>. This is what Nix expression authors see. It can also be used when installing using <command>nix-env -iA</command>.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      The filename for (the directory containing) the Nix expression.
+     </para>
+    </listitem>
+   </itemizedlist>
+   Most of the time, these are the same. For instance, the package <literal>e2fsprogs</literal> has a <varname>name</varname> attribute <literal>"e2fsprogs-<replaceable>version</replaceable>"</literal>, is bound to the variable name <varname>e2fsprogs</varname> in <filename>all-packages.nix</filename>, and the Nix expression is in <filename>pkgs/os-specific/linux/e2fsprogs/default.nix</filename>.
+  </para>
+
+  <para>
+   There are a few naming guidelines:
+   <itemizedlist>
+    <listitem>
+     <para>
+      The <literal>name</literal> attribute <emphasis>should</emphasis> be identical to the upstream package name.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      The <literal>name</literal> attribute <emphasis>must not</emphasis> contain uppercase letters — e.g., <literal>"mplayer-1.0rc2"</literal> instead of <literal>"MPlayer-1.0rc2"</literal>.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      The version part of the <literal>name</literal> attribute <emphasis>must</emphasis> start with a digit (following a dash) — e.g., <literal>"hello-0.3.1rc2"</literal>.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      If a package is not a release but a commit from a repository, then the version part of the name <emphasis>must</emphasis> be the date of that (fetched) commit. The date <emphasis>must</emphasis> be in <literal>"YYYY-MM-DD"</literal> format. Also append <literal>"unstable"</literal> to the name - e.g., <literal>"pkgname-unstable-2014-09-23"</literal>.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Dashes in the package name <emphasis>should</emphasis> be preserved in new variable names, rather than converted to underscores or camel cased — e.g., <varname>http-parser</varname> instead of <varname>http_parser</varname> or <varname>httpParser</varname>. The hyphenated style is preferred in all three package names.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      If there are multiple versions of a package, this <emphasis>should</emphasis> be reflected in the variable names in <filename>all-packages.nix</filename>, e.g. <varname>json-c-0-9</varname> and <varname>json-c-0-11</varname>. If there is an obvious “default” version, make an attribute like <literal>json-c = json-c-0-9;</literal>. See also <xref linkend="sec-versioning" />
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+ </section>
+ <section xml:id="sec-organisation">
+  <title>File naming and organisation</title>
+
+  <para>
+   Names of files and directories should be in lowercase, with dashes between words — not in camel case. For instance, it should be <filename>all-packages.nix</filename>, not <filename>allPackages.nix</filename> or <filename>AllPackages.nix</filename>.
+  </para>
+
+  <section xml:id="sec-hierarchy">
+   <title>Hierarchy</title>
+
+   <para>
+    Each package should be stored in its own directory somewhere in the <filename>pkgs/</filename> tree, i.e. in <filename>pkgs/<replaceable>category</replaceable>/<replaceable>subcategory</replaceable>/<replaceable>...</replaceable>/<replaceable>pkgname</replaceable></filename>. Below are some rules for picking the right category for a package. Many packages fall under several categories; what matters is the <emphasis>primary</emphasis> purpose of a package. For example, the <literal>libxml2</literal> package builds both a library and some tools; but it’s a library foremost, so it goes under <filename>pkgs/development/libraries</filename>.
+   </para>
+
+   <para>
+    When in doubt, consider refactoring the <filename>pkgs/</filename> tree, e.g. creating new categories or splitting up an existing category.
+   </para>
+
+   <variablelist>
+    <varlistentry>
+     <term>
+      If it’s used to support <emphasis>software development</emphasis>:
+     </term>
+     <listitem>
+      <variablelist>
+       <varlistentry>
+        <term>
+         If it’s a <emphasis>library</emphasis> used by other packages:
+        </term>
+        <listitem>
+         <para>
+          <filename>development/libraries</filename> (e.g. <filename>libxml2</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s a <emphasis>compiler</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>development/compilers</filename> (e.g. <filename>gcc</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s an <emphasis>interpreter</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>development/interpreters</filename> (e.g. <filename>guile</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s a (set of) development <emphasis>tool(s)</emphasis>:
+        </term>
+        <listitem>
+         <variablelist>
+          <varlistentry>
+           <term>
+            If it’s a <emphasis>parser generator</emphasis> (including lexers):
+           </term>
+           <listitem>
+            <para>
+             <filename>development/tools/parsing</filename> (e.g. <filename>bison</filename>, <filename>flex</filename>)
+            </para>
+           </listitem>
+          </varlistentry>
+          <varlistentry>
+           <term>
+            If it’s a <emphasis>build manager</emphasis>:
+           </term>
+           <listitem>
+            <para>
+             <filename>development/tools/build-managers</filename> (e.g. <filename>gnumake</filename>)
+            </para>
+           </listitem>
+          </varlistentry>
+          <varlistentry>
+           <term>
+            Else:
+           </term>
+           <listitem>
+            <para>
+             <filename>development/tools/misc</filename> (e.g. <filename>binutils</filename>)
+            </para>
+           </listitem>
+          </varlistentry>
+         </variablelist>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         Else:
+        </term>
+        <listitem>
+         <para>
+          <filename>development/misc</filename>
+         </para>
+        </listitem>
+       </varlistentry>
+      </variablelist>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      If it’s a (set of) <emphasis>tool(s)</emphasis>:
+     </term>
+     <listitem>
+      <para>
+       (A tool is a relatively small program, especially one intended to be used non-interactively.)
+      </para>
+      <variablelist>
+       <varlistentry>
+        <term>
+         If it’s for <emphasis>networking</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>tools/networking</filename> (e.g. <filename>wget</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s for <emphasis>text processing</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>tools/text</filename> (e.g. <filename>diffutils</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s a <emphasis>system utility</emphasis>, i.e., something related or essential to the operation of a system:
+        </term>
+        <listitem>
+         <para>
+          <filename>tools/system</filename> (e.g. <filename>cron</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s an <emphasis>archiver</emphasis> (which may include a compression function):
+        </term>
+        <listitem>
+         <para>
+          <filename>tools/archivers</filename> (e.g. <filename>zip</filename>, <filename>tar</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s a <emphasis>compression</emphasis> program:
+        </term>
+        <listitem>
+         <para>
+          <filename>tools/compression</filename> (e.g. <filename>gzip</filename>, <filename>bzip2</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s a <emphasis>security</emphasis>-related program:
+        </term>
+        <listitem>
+         <para>
+          <filename>tools/security</filename> (e.g. <filename>nmap</filename>, <filename>gnupg</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         Else:
+        </term>
+        <listitem>
+         <para>
+          <filename>tools/misc</filename>
+         </para>
+        </listitem>
+       </varlistentry>
+      </variablelist>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      If it’s a <emphasis>shell</emphasis>:
+     </term>
+     <listitem>
+      <para>
+       <filename>shells</filename> (e.g. <filename>bash</filename>)
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      If it’s a <emphasis>server</emphasis>:
+     </term>
+     <listitem>
+      <variablelist>
+       <varlistentry>
+        <term>
+         If it’s a web server:
+        </term>
+        <listitem>
+         <para>
+          <filename>servers/http</filename> (e.g. <filename>apache-httpd</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s an implementation of the X Windowing System:
+        </term>
+        <listitem>
+         <para>
+          <filename>servers/x11</filename> (e.g. <filename>xorg</filename> — this includes the client libraries and programs)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         Else:
+        </term>
+        <listitem>
+         <para>
+          <filename>servers/misc</filename>
+         </para>
+        </listitem>
+       </varlistentry>
+      </variablelist>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      If it’s a <emphasis>desktop environment</emphasis>:
+     </term>
+     <listitem>
+      <para>
+       <filename>desktops</filename> (e.g. <filename>kde</filename>, <filename>gnome</filename>, <filename>enlightenment</filename>)
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      If it’s a <emphasis>window manager</emphasis>:
+     </term>
+     <listitem>
+      <para>
+       <filename>applications/window-managers</filename> (e.g. <filename>awesome</filename>, <filename>stumpwm</filename>)
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      If it’s an <emphasis>application</emphasis>:
+     </term>
+     <listitem>
+      <para>
+       A (typically large) program with a distinct user interface, primarily used interactively.
+      </para>
+      <variablelist>
+       <varlistentry>
+        <term>
+         If it’s a <emphasis>version management system</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>applications/version-management</filename> (e.g. <filename>subversion</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s for <emphasis>video playback / editing</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>applications/video</filename> (e.g. <filename>vlc</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s for <emphasis>graphics viewing / editing</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>applications/graphics</filename> (e.g. <filename>gimp</filename>)
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s for <emphasis>networking</emphasis>:
+        </term>
+        <listitem>
+         <variablelist>
+          <varlistentry>
+           <term>
+            If it’s a <emphasis>mailreader</emphasis>:
+           </term>
+           <listitem>
+            <para>
+             <filename>applications/networking/mailreaders</filename> (e.g. <filename>thunderbird</filename>)
+            </para>
+           </listitem>
+          </varlistentry>
+          <varlistentry>
+           <term>
+            If it’s a <emphasis>newsreader</emphasis>:
+           </term>
+           <listitem>
+            <para>
+             <filename>applications/networking/newsreaders</filename> (e.g. <filename>pan</filename>)
+            </para>
+           </listitem>
+          </varlistentry>
+          <varlistentry>
+           <term>
+            If it’s a <emphasis>web browser</emphasis>:
+           </term>
+           <listitem>
+            <para>
+             <filename>applications/networking/browsers</filename> (e.g. <filename>firefox</filename>)
+            </para>
+           </listitem>
+          </varlistentry>
+          <varlistentry>
+           <term>
+            Else:
+           </term>
+           <listitem>
+            <para>
+             <filename>applications/networking/misc</filename>
+            </para>
+           </listitem>
+          </varlistentry>
+         </variablelist>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         Else:
+        </term>
+        <listitem>
+         <para>
+          <filename>applications/misc</filename>
+         </para>
+        </listitem>
+       </varlistentry>
+      </variablelist>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      If it’s <emphasis>data</emphasis> (i.e., does not have a straight-forward executable semantics):
+     </term>
+     <listitem>
+      <variablelist>
+       <varlistentry>
+        <term>
+         If it’s a <emphasis>font</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>data/fonts</filename>
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s an <emphasis>icon theme</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>data/icons</filename>
+         </para>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s related to <emphasis>SGML/XML processing</emphasis>:
+        </term>
+        <listitem>
+         <variablelist>
+          <varlistentry>
+           <term>
+            If it’s an <emphasis>XML DTD</emphasis>:
+           </term>
+           <listitem>
+            <para>
+             <filename>data/sgml+xml/schemas/xml-dtd</filename> (e.g. <filename>docbook</filename>)
+            </para>
+           </listitem>
+          </varlistentry>
+          <varlistentry>
+           <term>
+            If it’s an <emphasis>XSLT stylesheet</emphasis>:
+           </term>
+           <listitem>
+            <para>
+             (Okay, these are executable...)
+            </para>
+            <para>
+             <filename>data/sgml+xml/stylesheets/xslt</filename> (e.g. <filename>docbook-xsl</filename>)
+            </para>
+           </listitem>
+          </varlistentry>
+         </variablelist>
+        </listitem>
+       </varlistentry>
+       <varlistentry>
+        <term>
+         If it’s a <emphasis>theme</emphasis> for a <emphasis>desktop environment</emphasis>,
+         a <emphasis>window manager</emphasis> or a <emphasis>display manager</emphasis>:
+        </term>
+        <listitem>
+         <para>
+          <filename>data/themes</filename>
+         </para>
+        </listitem>
+       </varlistentry>
+      </variablelist>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      If it’s a <emphasis>game</emphasis>:
+     </term>
+     <listitem>
+      <para>
+       <filename>games</filename>
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      Else:
+     </term>
+     <listitem>
+      <para>
+       <filename>misc</filename>
+      </para>
+     </listitem>
+    </varlistentry>
+   </variablelist>
+  </section>
+
+  <section xml:id="sec-versioning">
+   <title>Versioning</title>
+
+   <para>
+    Because every version of a package in Nixpkgs creates a potential maintenance burden, old versions of a package should not be kept unless there is a good reason to do so. For instance, Nixpkgs contains several versions of GCC because other packages don’t build with the latest version of GCC. Other examples are having both the latest stable and latest pre-release version of a package, or to keep several major releases of an application that differ significantly in functionality.
+   </para>
+
+   <para>
+    If there is only one version of a package, its Nix expression should be named <filename>e2fsprogs/default.nix</filename>. If there are multiple versions, this should be reflected in the filename, e.g. <filename>e2fsprogs/1.41.8.nix</filename> and <filename>e2fsprogs/1.41.9.nix</filename>. The version in the filename should leave out unnecessary detail. For instance, if we keep the latest Firefox 2.0.x and 3.5.x versions in Nixpkgs, they should be named <filename>firefox/2.0.nix</filename> and <filename>firefox/3.5.nix</filename>, respectively (which, at a given point, might contain versions <literal>2.0.0.20</literal> and <literal>3.5.4</literal>). If a version requires many auxiliary files, you can use a subdirectory for each version, e.g. <filename>firefox/2.0/default.nix</filename> and <filename>firefox/3.5/default.nix</filename>.
+   </para>
+
+   <para>
+    All versions of a package <emphasis>must</emphasis> be included in <filename>all-packages.nix</filename> to make sure that they evaluate correctly.
+   </para>
+  </section>
+ </section>
+ <section xml:id="sec-sources">
+  <title>Fetching Sources</title>
+
+  <para>
+   There are multiple ways to fetch a package source in nixpkgs. The general guideline is that you should package reproducible sources with a high degree of availability. Right now there is only one fetcher which has mirroring support and that is <literal>fetchurl</literal>. Note that you should also prefer protocols which have a corresponding proxy environment variable.
+  </para>
+
+  <para>
+   You can find many source fetch helpers in <literal>pkgs/build-support/fetch*</literal>.
+  </para>
+
+  <para>
+   In the file <literal>pkgs/top-level/all-packages.nix</literal> you can find fetch helpers, these have names on the form <literal>fetchFrom*</literal>. The intention of these are to provide snapshot fetches but using the same api as some of the version controlled fetchers from <literal>pkgs/build-support/</literal>. As an example going from bad to good:
+   <itemizedlist>
+    <listitem>
+     <para>
+      Bad: Uses <literal>git://</literal> which won't be proxied.
+<programlisting>
+src = fetchgit {
+  url = "git://github.com/NixOS/nix.git";
+  rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
+  sha256 = "1cw5fszffl5pkpa6s6wjnkiv6lm5k618s32sp60kvmvpy7a2v9kg";
+}
+</programlisting>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Better: This is ok, but an archive fetch will still be faster.
+<programlisting>
+src = fetchgit {
+  url = "https://github.com/NixOS/nix.git";
+  rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
+  sha256 = "1cw5fszffl5pkpa6s6wjnkiv6lm5k618s32sp60kvmvpy7a2v9kg";
+}
+</programlisting>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Best: Fetches a snapshot archive and you get the rev you want.
+<programlisting>
+src = fetchFromGitHub {
+  owner = "NixOS";
+  repo = "nix";
+  rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
+  sha256 = "1i2yxndxb6yc9l6c99pypbd92lfq5aac4klq7y2v93c9qvx2cgpc";
+}
+</programlisting>
+      Find the value to put as <literal>sha256</literal> by running <literal>nix run -f '&lt;nixpkgs&gt;' nix-prefetch-github -c nix-prefetch-github --rev 1f795f9f44607cc5bec70d1300150bfefcef2aae NixOS nix</literal> or <literal>nix-prefetch-url --unpack https://github.com/NixOS/nix/archive/1f795f9f44607cc5bec70d1300150bfefcef2aae.tar.gz</literal>.
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+ </section>
+ <section xml:id="sec-source-hashes">
+  <title>Obtaining source hash</title>
+
+  <para>
+   Preferred source hash type is sha256. There are several ways to get it.
+  </para>
+
+  <orderedlist>
+   <listitem>
+    <para>
+     Prefetch URL (with <literal>nix-prefetch-<replaceable>XXX</replaceable> <replaceable>URL</replaceable></literal>, where <replaceable>XXX</replaceable> is one of <literal>url</literal>, <literal>git</literal>, <literal>hg</literal>, <literal>cvs</literal>, <literal>bzr</literal>, <literal>svn</literal>). Hash is printed to stdout.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Prefetch by package source (with <literal>nix-prefetch-url '&lt;nixpkgs&gt;' -A <replaceable>PACKAGE</replaceable>.src</literal>, where <replaceable>PACKAGE</replaceable> is package attribute name). Hash is printed to stdout.
+    </para>
+    <para>
+     This works well when you've upgraded existing package version and want to find out new hash, but is useless if package can't be accessed by attribute or package has multiple sources (<literal>.srcs</literal>, architecture-dependent sources, etc).
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Upstream provided hash: use it when upstream provides <literal>sha256</literal> or <literal>sha512</literal> (when upstream provides <literal>md5</literal>, don't use it, compute <literal>sha256</literal> instead).
+    </para>
+    <para>
+     A little nuance is that <literal>nix-prefetch-*</literal> tools produce hash encoded with <literal>base32</literal>, but upstream usually provides hexadecimal (<literal>base16</literal>) encoding. Fetchers understand both formats. Nixpkgs does not standardize on any one format.
+    </para>
+    <para>
+     You can convert between formats with nix-hash, for example:
+<screen>
+<prompt>$ </prompt>nix-hash --type sha256 --to-base32 <replaceable>HASH</replaceable>
+</screen>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Extracting hash from local source tarball can be done with <literal>sha256sum</literal>. Use <literal>nix-prefetch-url file:///path/to/tarball </literal> if you want base32 hash.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Fake hash: set fake hash in package expression, perform build and extract correct hash from error Nix prints.
+    </para>
+    <para>
+     For package updates it is enough to change one symbol to make hash fake. For new packages, you can use <literal>lib.fakeSha256</literal>, <literal>lib.fakeSha512</literal> or any other fake hash.
+    </para>
+    <para>
+     This is last resort method when reconstructing source URL is non-trivial and <literal>nix-prefetch-url -A</literal> isn't applicable (for example, <link xlink:href="https://github.com/NixOS/nixpkgs/blob/d2ab091dd308b99e4912b805a5eb088dd536adb9/pkgs/applications/video/kodi/default.nix#L73"> one of <literal>kodi</literal> dependencies</link>). The easiest way then would be replace hash with a fake one and rebuild. Nix build will fail and error message will contain desired hash.
+    </para>
+    <warning>
+     <para>
+      This method has security problems. Check below for details.
+     </para>
+    </warning>
+   </listitem>
+  </orderedlist>
+
+  <section xml:id="sec-source-hashes-security">
+   <title>Obtaining hashes securely</title>
+
+   <para>
+    Let's say Man-in-the-Middle (MITM) sits close to your network. Then instead of fetching source you can fetch malware, and instead of source hash you get hash of malware. Here are security considerations for this scenario:
+   </para>
+
+   <itemizedlist>
+    <listitem>
+     <para>
+      <literal>http://</literal> URLs are not secure to prefetch hash from;
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      hashes from upstream (in method 3) should be obtained via secure protocol;
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      <literal>https://</literal> URLs are secure in methods 1, 2, 3;
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      <literal>https://</literal> URLs are not secure in method 5. When obtaining hashes with fake hash method, TLS checks are disabled. So refetch source hash from several different networks to exclude MITM scenario. Alternatively, use fake hash method to make Nix error, but instead of extracting hash from error, extract <literal>https://</literal> URL and prefetch it with method 1.
+     </para>
+    </listitem>
+   </itemizedlist>
+  </section>
+ </section>
+ <section xml:id="sec-patches">
+  <title>Patches</title>
+
+  <para>
+   Patches available online should be retrieved using <literal>fetchpatch</literal>.
+  </para>
+
+  <para>
+<programlisting>
+patches = [
+  (fetchpatch {
+    name = "fix-check-for-using-shared-freetype-lib.patch";
+    url = "http://git.ghostscript.com/?p=ghostpdl.git;a=patch;h=8f5d285";
+    sha256 = "1f0k043rng7f0rfl9hhb89qzvvksqmkrikmm38p61yfx51l325xr";
+  })
+];
+</programlisting>
+  </para>
+
+  <para>
+   Otherwise, you can add a <literal>.patch</literal> file to the <literal>nixpkgs</literal> repository. In the interest of keeping our maintenance burden to a minimum, only patches that are unique to <literal>nixpkgs</literal> should be added in this way.
+  </para>
+
+  <para>
+<programlisting>
+patches = [ ./0001-changes.patch ];
+</programlisting>
+  </para>
+
+  <para>
+   If you do need to do create this sort of patch file, one way to do so is with git:
+   <orderedlist>
+    <listitem>
+     <para>
+      Move to the root directory of the source code you're patching.
+<screen>
+<prompt>$ </prompt>cd the/program/source</screen>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      If a git repository is not already present, create one and stage all of the source files.
+<screen>
+<prompt>$ </prompt>git init
+<prompt>$ </prompt>git add .</screen>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Edit some files to make whatever changes need to be included in the patch.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Use git to create a diff, and pipe the output to a patch file:
+<screen>
+<prompt>$ </prompt>git diff > nixpkgs/pkgs/the/package/0001-changes.patch</screen>
+     </para>
+    </listitem>
+   </orderedlist>
+  </para>
+ </section>
+</chapter>

third_party/nixpkgs/doc/contributing/contributing-to-documentation.xml

@@ -0,0 +1,30 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="chap-contributing">
+ <title>Contributing to this documentation</title>
+ <para>
+  The DocBook sources of the Nixpkgs manual are in the <filename
+xlink:href="https://github.com/NixOS/nixpkgs/tree/master/doc">doc</filename> subdirectory of the Nixpkgs repository.
+ </para>
+ <para>
+  You can quickly check your edits with <command>make</command>:
+ </para>
+<screen>
+<prompt>$ </prompt>cd /path/to/nixpkgs/doc
+<prompt>$ </prompt>nix-shell
+<prompt>[nix-shell]$ </prompt>make
+</screen>
+ <para>
+  If you experience problems, run <command>make debug</command> to help understand the docbook errors.
+ </para>
+ <para>
+  After making modifications to the manual, it's important to build it before committing. You can do that as follows:
+<screen>
+<prompt>$ </prompt>cd /path/to/nixpkgs/doc
+<prompt>$ </prompt>nix-shell
+<prompt>[nix-shell]$ </prompt>make clean
+<prompt>[nix-shell]$ </prompt>nix-build .
+</screen>
+  If the build succeeds, the manual will be in <filename>./result/share/doc/nixpkgs/manual.html</filename>.
+ </para>
+</chapter>

third_party/nixpkgs/doc/contributing/quick-start.xml

@@ -0,0 +1,152 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="chap-quick-start">
+ <title>Quick Start to Adding a Package</title>
+ <para>
+  To add a package to Nixpkgs:
+  <orderedlist>
+   <listitem>
+    <para>
+     Checkout the Nixpkgs source tree:
+<screen>
+<prompt>$ </prompt>git clone https://github.com/NixOS/nixpkgs
+<prompt>$ </prompt>cd nixpkgs</screen>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Find a good place in the Nixpkgs tree to add the Nix expression for your package. For instance, a library package typically goes into <filename>pkgs/development/libraries/<replaceable>pkgname</replaceable></filename>, while a web browser goes into <filename>pkgs/applications/networking/browsers/<replaceable>pkgname</replaceable></filename>. See <xref linkend="sec-organisation" /> for some hints on the tree organisation. Create a directory for your package, e.g.
+<screen>
+<prompt>$ </prompt>mkdir pkgs/development/libraries/libfoo</screen>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     In the package directory, create a Nix expression — a piece of code that describes how to build the package. In this case, it should be a <emphasis>function</emphasis> that is called with the package dependencies as arguments, and returns a build of the package in the Nix store. The expression should usually be called <filename>default.nix</filename>.
+<screen>
+<prompt>$ </prompt>emacs pkgs/development/libraries/libfoo/default.nix
+<prompt>$ </prompt>git add pkgs/development/libraries/libfoo/default.nix</screen>
+    </para>
+    <para>
+     You can have a look at the existing Nix expressions under <filename>pkgs/</filename> to see how it’s done. Here are some good ones:
+     <itemizedlist>
+      <listitem>
+       <para>
+        GNU Hello: <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/misc/hello/default.nix"><filename>pkgs/applications/misc/hello/default.nix</filename></link>. Trivial package, which specifies some <varname>meta</varname> attributes which is good practice.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        GNU cpio: <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/tools/archivers/cpio/default.nix"><filename>pkgs/tools/archivers/cpio/default.nix</filename></link>. Also a simple package. The generic builder in <varname>stdenv</varname> does everything for you. It has no dependencies beyond <varname>stdenv</varname>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        GNU Multiple Precision arithmetic library (GMP): <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/libraries/gmp/5.1.x.nix"><filename>pkgs/development/libraries/gmp/5.1.x.nix</filename></link>. Also done by the generic builder, but has a dependency on <varname>m4</varname>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Pan, a GTK-based newsreader: <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/networking/newsreaders/pan/default.nix"><filename>pkgs/applications/networking/newsreaders/pan/default.nix</filename></link>. Has an optional dependency on <varname>gtkspell</varname>, which is only built if <varname>spellCheck</varname> is <literal>true</literal>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Apache HTTPD: <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/http/apache-httpd/2.4.nix"><filename>pkgs/servers/http/apache-httpd/2.4.nix</filename></link>. A bunch of optional features, variable substitutions in the configure flags, a post-install hook, and miscellaneous hackery.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Thunderbird: <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/networking/mailreaders/thunderbird/default.nix"><filename>pkgs/applications/networking/mailreaders/thunderbird/default.nix</filename></link>. Lots of dependencies.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        JDiskReport, a Java utility: <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/tools/misc/jdiskreport/default.nix"><filename>pkgs/tools/misc/jdiskreport/default.nix</filename></link>. Nixpkgs doesn’t have a decent <varname>stdenv</varname> for Java yet so this is pretty ad-hoc.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        XML::Simple, a Perl module: <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/perl-packages.nix"><filename>pkgs/top-level/perl-packages.nix</filename></link> (search for the <varname>XMLSimple</varname> attribute). Most Perl modules are so simple to build that they are defined directly in <filename>perl-packages.nix</filename>; no need to make a separate file for them.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Adobe Reader: <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/misc/adobe-reader/default.nix"><filename>pkgs/applications/misc/adobe-reader/default.nix</filename></link>. Shows how binary-only packages can be supported. In particular the <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/misc/adobe-reader/builder.sh">builder</link> uses <command>patchelf</command> to set the RUNPATH and ELF interpreter of the executables so that the right libraries are found at runtime.
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+    <para>
+     Some notes:
+     <itemizedlist>
+      <listitem>
+       <para>
+        All <varname linkend="chap-meta">meta</varname> attributes are optional, but it’s still a good idea to provide at least the <varname>description</varname>, <varname>homepage</varname> and <varname
+          linkend="sec-meta-license">license</varname>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        You can use <command>nix-prefetch-url</command> <replaceable>url</replaceable> to get the SHA-256 hash of source distributions. There are similar commands as <command>nix-prefetch-git</command> and <command>nix-prefetch-hg</command> available in <literal>nix-prefetch-scripts</literal> package.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        A list of schemes for <literal>mirror://</literal> URLs can be found in <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/fetchurl/mirrors.nix"><filename>pkgs/build-support/fetchurl/mirrors.nix</filename></link>.
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+    <para>
+     The exact syntax and semantics of the Nix expression language, including the built-in function, are described in the Nix manual in the <link
+    xlink:href="http://hydra.nixos.org/job/nix/trunk/tarball/latest/download-by-type/doc/manual/#chap-writing-nix-expressions">chapter on writing Nix expressions</link>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Add a call to the function defined in the previous step to <link
+    xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/all-packages.nix"><filename>pkgs/top-level/all-packages.nix</filename></link> with some descriptive name for the variable, e.g. <varname>libfoo</varname>.
+<screen>
+<prompt>$ </prompt>emacs pkgs/top-level/all-packages.nix</screen>
+    </para>
+    <para>
+     The attributes in that file are sorted by category (like “Development / Libraries”) that more-or-less correspond to the directory structure of Nixpkgs, and then by attribute name.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     To test whether the package builds, run the following command from the root of the nixpkgs source tree:
+<screen>
+<prompt>$ </prompt>nix-build -A libfoo</screen>
+     where <varname>libfoo</varname> should be the variable name defined in the previous step. You may want to add the flag <option>-K</option> to keep the temporary build directory in case something fails. If the build succeeds, a symlink <filename>./result</filename> to the package in the Nix store is created.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     If you want to install the package into your profile (optional), do
+<screen>
+<prompt>$ </prompt>nix-env -f . -iA libfoo</screen>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Optionally commit the new package and open a pull request <link
+     xlink:href="https://github.com/NixOS/nixpkgs/pulls">to nixpkgs</link>, or use <link
+     xlink:href="https://discourse.nixos.org/t/about-the-patches-category/477"> the Patches category</link> on Discourse for sending a patch without a GitHub account.
+    </para>
+   </listitem>
+  </orderedlist>
+ </para>
+</chapter>

third_party/nixpkgs/doc/contributing/reviewing-contributions.xml

@@ -0,0 +1,536 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+        xmlns:xlink="http://www.w3.org/1999/xlink"
+        xmlns:xi="http://www.w3.org/2001/XInclude"
+        version="5.0"
+        xml:id="chap-reviewing-contributions">
+ <title>Reviewing contributions</title>
+ <warning>
+  <para>
+   The following section is a draft, and the policy for reviewing is still being discussed in issues such as <link
+	   xlink:href="https://github.com/NixOS/nixpkgs/issues/11166">#11166 </link> and <link
+	   xlink:href="https://github.com/NixOS/nixpkgs/issues/20836">#20836 </link>.
+  </para>
+ </warning>
+ <para>
+  The Nixpkgs project receives a fairly high number of contributions via GitHub pull requests. Reviewing and approving these is an important task and a way to contribute to the project.
+ </para>
+ <para>
+  The high change rate of Nixpkgs makes any pull request that remains open for too long subject to conflicts that will require extra work from the submitter or the merger. Reviewing pull requests in a timely manner and being responsive to the comments is the key to avoid this issue. GitHub provides sort filters that can be used to see the <link
+  xlink:href="https://github.com/NixOS/nixpkgs/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-desc">most recently</link> and the <link
+  xlink:href="https://github.com/NixOS/nixpkgs/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-asc">least recently</link> updated pull requests. We highly encourage looking at <link xlink:href="https://github.com/NixOS/nixpkgs/pulls?q=is%3Apr+is%3Aopen+review%3Anone+status%3Asuccess+-label%3A%222.status%3A+work-in-progress%22+no%3Aproject+no%3Aassignee+no%3Amilestone"> this list of ready to merge, unreviewed pull requests</link>.
+ </para>
+ <para>
+  When reviewing a pull request, please always be nice and polite. Controversial changes can lead to controversial opinions, but it is important to respect every community member and their work.
+ </para>
+ <para>
+  GitHub provides reactions as a simple and quick way to provide feedback to pull requests or any comments. The thumb-down reaction should be used with care and if possible accompanied with some explanation so the submitter has directions to improve their contribution.
+ </para>
+ <para>
+  pull request reviews should include a list of what has been reviewed in a comment, so other reviewers and mergers can know the state of the review.
+ </para>
+ <para>
+  All the review template samples provided in this section are generic and meant as examples. Their usage is optional and the reviewer is free to adapt them to their liking.
+ </para>
+ <section xml:id="reviewing-contributions-package-updates">
+  <title>Package updates</title>
+
+  <para>
+   A package update is the most trivial and common type of pull request. These pull requests mainly consist of updating the version part of the package name and the source hash.
+  </para>
+
+  <para>
+   It can happen that non-trivial updates include patches or more complex changes.
+  </para>
+
+  <para>
+   Reviewing process:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Add labels to the pull request. (Requires commit rights)
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       <literal>8.has: package (update)</literal> and any topic label that fit the updated package.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the package versioning fits the guidelines.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the commit text fits the guidelines.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the package maintainers are notified.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       <link xlink:href="https://help.github.com/articles/about-codeowners/">CODEOWNERS</link> will make GitHub notify users based on the submitted changes, but it can happen that it misses some of the package maintainers.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the meta field information is correct.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       License can change with version updates, so it should be checked to match the upstream license.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       If the package has no maintainer, a maintainer must be set. This can be the update submitter or a community member that accepts to take maintainership of the package.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the code contains no typos.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Building the package locally.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       pull requests are often targeted to the master or staging branch, and building the pull request locally when it is submitted can trigger many source builds.
+      </para>
+      <para>
+       It is possible to rebase the changes on nixos-unstable or nixpkgs-unstable for easier review by running the following commands from a nixpkgs clone.
+<screen>
+<prompt>$ </prompt>git fetch origin nixos-unstable <co xml:id='reviewing-rebase-2' />
+<prompt>$ </prompt>git fetch origin pull/PRNUMBER/head <co xml:id='reviewing-rebase-3' />
+<prompt>$ </prompt>git rebase --onto nixos-unstable BASEBRANCH FETCH_HEAD <co
+  xml:id='reviewing-rebase-4' />
+</screen>
+       <calloutlist>
+        <callout arearefs='reviewing-rebase-2'>
+         <para>
+          Fetching the nixos-unstable branch.
+         </para>
+        </callout>
+        <callout arearefs='reviewing-rebase-3'>
+         <para>
+          Fetching the pull request changes, <varname>PRNUMBER</varname> is the number at the end of the pull request title and <varname>BASEBRANCH</varname> the base branch of the pull request.
+         </para>
+        </callout>
+        <callout arearefs='reviewing-rebase-4'>
+         <para>
+          Rebasing the pull request changes to the nixos-unstable branch.
+         </para>
+        </callout>
+       </calloutlist>
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       The <link xlink:href="https://github.com/Mic92/nixpkgs-review">nixpkgs-review</link> tool can be used to review a pull request content in a single command. <varname>PRNUMBER</varname> should be replaced by the number at the end of the pull request title. You can also provide the full github pull request url.
+      </para>
+<screen>
+<prompt>$ </prompt>nix-shell -p nixpkgs-review --run "nixpkgs-review pr PRNUMBER"
+</screen>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Running every binary.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <example xml:id="reviewing-contributions-sample-package-update">
+   <title>Sample template for a package update review</title>
+<screen>
+##### Reviewed points
+
+- [ ] package name fits guidelines
+- [ ] package version fits guidelines
+- [ ] package build on ARCHITECTURE
+- [ ] executables tested on ARCHITECTURE
+- [ ] all depending packages build
+
+##### Possible improvements
+
+##### Comments
+
+</screen>
+  </example>
+ </section>
+ <section xml:id="reviewing-contributions-new-packages">
+  <title>New packages</title>
+
+  <para>
+   New packages are a common type of pull requests. These pull requests consists in adding a new nix-expression for a package.
+  </para>
+
+  <para>
+   Reviewing process:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Add labels to the pull request. (Requires commit rights)
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       <literal>8.has: package (new)</literal> and any topic label that fit the new package.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the package versioning is fitting the guidelines.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the commit name is fitting the guidelines.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the meta field contains correct information.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       License must be checked to be fitting upstream license.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       Platforms should be set or the package will not get binary substitutes.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       A maintainer must be set. This can be the package submitter or a community member that accepts to take maintainership of the package.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the code contains no typos.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure the package source.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       Mirrors urls should be used when available.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       The most appropriate function should be used (e.g. packages from GitHub should use <literal>fetchFromGitHub</literal>).
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Building the package locally.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Running every binary.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <example xml:id="reviewing-contributions-sample-new-package">
+   <title>Sample template for a new package review</title>
+<screen>
+##### Reviewed points
+
+- [ ] package path fits guidelines
+- [ ] package name fits guidelines
+- [ ] package version fits guidelines
+- [ ] package build on ARCHITECTURE
+- [ ] executables tested on ARCHITECTURE
+- [ ] `meta.description` is set and fits guidelines
+- [ ] `meta.license` fits upstream license
+- [ ] `meta.platforms` is set
+- [ ] `meta.maintainers` is set
+- [ ] build time only dependencies are declared in `nativeBuildInputs`
+- [ ] source is fetched using the appropriate function
+- [ ] phases are respected
+- [ ] patches that are remotely available are fetched with `fetchpatch`
+
+##### Possible improvements
+
+##### Comments
+
+</screen>
+  </example>
+ </section>
+ <section xml:id="reviewing-contributions-module-updates">
+  <title>Module updates</title>
+
+  <para>
+   Module updates are submissions changing modules in some ways. These often contains changes to the options or introduce new options.
+  </para>
+
+  <para>
+   Reviewing process
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Add labels to the pull request. (Requires commit rights)
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       <literal>8.has: module (update)</literal> and any topic label that fit the module.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the module maintainers are notified.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       <link xlink:href="https://help.github.com/articles/about-codeowners/">CODEOWNERS</link> will make GitHub notify users based on the submitted changes, but it can happen that it misses some of the package maintainers.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the module tests, if any, are succeeding.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the introduced options are correct.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       Type should be appropriate (string related types differs in their merging capabilities, <literal>optionSet</literal> and <literal>string</literal> types are deprecated).
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       Description, default and example should be provided.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that option changes are backward compatible.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       <literal>mkRenamedOptionModule</literal> and <literal>mkAliasOptionModule</literal> functions provide way to make option changes backward compatible.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that removed options are declared with <literal>mkRemovedOptionModule</literal>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that changes that are not backward compatible are mentioned in release notes.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that documentations affected by the change is updated.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <example xml:id="reviewing-contributions-sample-module-update">
+   <title>Sample template for a module update review</title>
+<screen>
+##### Reviewed points
+
+- [ ] changes are backward compatible
+- [ ] removed options are declared with `mkRemovedOptionModule`
+- [ ] changes that are not backward compatible are documented in release notes
+- [ ] module tests succeed on ARCHITECTURE
+- [ ] options types are appropriate
+- [ ] options description is set
+- [ ] options example is provided
+- [ ] documentation affected by the changes is updated
+
+##### Possible improvements
+
+##### Comments
+
+</screen>
+  </example>
+ </section>
+ <section xml:id="reviewing-contributions-new-modules">
+  <title>New modules</title>
+
+  <para>
+   New modules submissions introduce a new module to NixOS.
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Add labels to the pull request. (Requires commit rights)
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       <literal>8.has: module (new)</literal> and any topic label that fit the module.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the module tests, if any, are succeeding.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the introduced options are correct.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       Type should be appropriate (string related types differs in their merging capabilities, <literal>optionSet</literal> and <literal>string</literal> types are deprecated).
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       Description, default and example should be provided.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that module <literal>meta</literal> field is present
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       Maintainers should be declared in <literal>meta.maintainers</literal>.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       Module documentation should be declared with <literal>meta.doc</literal>.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Ensure that the module respect other modules functionality.
+    </para>
+    <itemizedlist>
+     <listitem>
+      <para>
+       For example, enabling a module should not open firewall ports by default.
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+  </itemizedlist>
+
+  <example xml:id="reviewing-contributions-sample-new-module">
+   <title>Sample template for a new module review</title>
+<screen>
+##### Reviewed points
+
+- [ ] module path fits the guidelines
+- [ ] module tests succeed on ARCHITECTURE
+- [ ] options have appropriate types
+- [ ] options have default
+- [ ] options have example
+- [ ] options have descriptions
+- [ ] No unneeded package is added to environment.systemPackages
+- [ ] meta.maintainers is set
+- [ ] module documentation is declared in meta.doc
+
+##### Possible improvements
+
+##### Comments
+
+</screen>
+  </example>
+ </section>
+ <section xml:id="reviewing-contributions-other-submissions">
+  <title>Other submissions</title>
+
+  <para>
+   Other type of submissions requires different reviewing steps.
+  </para>
+
+  <para>
+   If you consider having enough knowledge and experience in a topic and would like to be a long-term reviewer for related submissions, please contact the current reviewers for that topic. They will give you information about the reviewing process. The main reviewers for a topic can be hard to find as there is no list, but checking past pull requests to see who reviewed or git-blaming the code to see who committed to that topic can give some hints.
+  </para>
+
+  <para>
+   Container system, boot system and library changes are some examples of the pull requests fitting this category.
+  </para>
+ </section>
+ <section xml:id="reviewing-contributions--merging-pull-requests">
+  <title>Merging pull requests</title>
+
+  <para>
+   It is possible for community members that have enough knowledge and experience on a special topic to contribute by merging pull requests.
+  </para>
+
+  <para>
+   TODO: add the procedure to request merging rights.
+  </para>
+
+<!--
+The following paragraph about how to deal with unactive contributors is just a
+proposition and should be modified to what the community agrees to be the right
+policy.
+
+<para>Please note that contributors with commit rights unactive for more than
+  three months will have their commit rights revoked.</para>
+-->
+
+  <para>
+   In a case a contributor definitively leaves the Nix community, they should create an issue or post on <link
+   xlink:href="https://discourse.nixos.org">Discourse</link> with references of packages and modules they maintain so the maintainership can be taken over by other contributors.
+  </para>
+ </section>
+</chapter>

third_party/nixpkgs/doc/contributing/submitting-changes.xml

@@ -0,0 +1,431 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="chap-submitting-changes">
+ <title>Submitting changes</title>
+ <section xml:id="submitting-changes-making-patches">
+  <title>Making patches</title>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Read <link xlink:href="https://nixos.org/nixpkgs/manual/">Manual (How to write packages for Nix)</link>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Fork <link xlink:href="https://github.com/nixos/nixpkgs/">the Nixpkgs repository</link> on GitHub.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Create a branch for your future fix.
+     <itemizedlist>
+      <listitem>
+       <para>
+        You can make branch from a commit of your local <command>nixos-version</command>. That will help you to avoid additional local compilations. Because you will receive packages from binary cache. For example
+<screen>
+<prompt>$ </prompt>nixos-version --hash
+0998212
+<prompt>$ </prompt>git checkout 0998212
+<prompt>$ </prompt>git checkout -b 'fix/pkg-name-update'
+</screen>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Please avoid working directly on the <command>master</command> branch.
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Make commits of logical units.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     If you removed pkgs or made some major NixOS changes, write about it in the release notes for the next stable release. For example <command>nixos/doc/manual/release-notes/rl-2003.xml</command>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Check for unnecessary whitespace with <command>git diff --check</command> before committing.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Format the commit in a following way:
+    </para>
+<programlisting>
+(pkg-name | nixos/&lt;module>): (from -> to | init at version | refactor | etc)
+Additional information.
+</programlisting>
+    <itemizedlist>
+     <listitem>
+      <para>
+       Examples:
+       <itemizedlist>
+        <listitem>
+         <para>
+          <command>nginx: init at 2.0.1</command>
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <command>firefox: 54.0.1 -> 55.0</command>
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <command>nixos/hydra: add bazBaz option</command>
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <command>nixos/nginx: refactor config generation</command>
+         </para>
+        </listitem>
+       </itemizedlist>
+      </para>
+     </listitem>
+    </itemizedlist>
+   </listitem>
+   <listitem>
+    <para>
+     Test your changes. If you work with
+     <itemizedlist>
+      <listitem>
+       <para>
+        nixpkgs:
+        <itemizedlist>
+         <listitem>
+          <para>
+           update pkg ->
+           <itemizedlist>
+            <listitem>
+             <para>
+              <command>nix-env -i pkg-name -f &lt;path to your local nixpkgs folder&gt;</command>
+             </para>
+            </listitem>
+           </itemizedlist>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           add pkg ->
+           <itemizedlist>
+            <listitem>
+             <para>
+              Make sure it's in <command>pkgs/top-level/all-packages.nix</command>
+             </para>
+            </listitem>
+            <listitem>
+             <para>
+              <command>nix-env -i pkg-name -f &lt;path to your local nixpkgs folder&gt;</command>
+             </para>
+            </listitem>
+           </itemizedlist>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           <emphasis>If you don't want to install pkg in you profile</emphasis>.
+           <itemizedlist>
+            <listitem>
+             <para>
+              <command>nix-build -A pkg-attribute-name &lt;path to your local nixpkgs folder&gt;/default.nix</command> and check results in the folder <command>result</command>. It will appear in the same directory where you did <command>nix-build</command>.
+             </para>
+            </listitem>
+           </itemizedlist>
+          </para>
+         </listitem>
+         <listitem>
+          <para>
+           If you did <command>nix-env -i pkg-name</command> you can do <command>nix-env -e pkg-name</command> to uninstall it from your system.
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        NixOS and its modules:
+        <itemizedlist>
+         <listitem>
+          <para>
+           You can add new module to your NixOS configuration file (usually it's <command>/etc/nixos/configuration.nix</command>). And do <command>sudo nixos-rebuild test -I nixpkgs=&lt;path to your local nixpkgs folder&gt; --fast</command>.
+          </para>
+         </listitem>
+        </itemizedlist>
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     If you have commits <command>pkg-name: oh, forgot to insert whitespace</command>: squash commits in this case. Use <command>git rebase -i</command>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     <link xlink:href="https://git-scm.com/book/en/v2/Git-Branching-Rebasing">Rebase</link> your branch against current <command>master</command>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </section>
+ <section xml:id="submitting-changes-submitting-changes">
+  <title>Submitting changes</title>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Push your changes to your fork of nixpkgs.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Create the pull request
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Follow <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md#submitting-changes">the contribution guidelines</link>.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </section>
+ <section xml:id="submitting-changes-submitting-security-fixes">
+  <title>Submitting security fixes</title>
+
+  <para>
+   Security fixes are submitted in the same way as other changes and thus the same guidelines apply.
+  </para>
+
+  <para>
+   If the security fix comes in the form of a patch and a CVE is available, then the name of the patch should be the CVE identifier, so e.g. <literal>CVE-2019-13636.patch</literal> in the case of a patch that is included in the Nixpkgs tree. If a patch is fetched the name needs to be set as well, e.g.:
+  </para>
+
+<programlisting>
+   (fetchpatch {
+     name = "CVE-2019-11068.patch";
+     url = "https://gitlab.gnome.org/GNOME/libxslt/commit/e03553605b45c88f0b4b2980adfbbb8f6fca2fd6.patch";
+     sha256 = "0pkpb4837km15zgg6h57bncp66d5lwrlvkr73h0lanywq7zrwhj8";
+   })
+  </programlisting>
+
+  <para>
+   If a security fix applies to both master and a stable release then, similar to regular changes, they are preferably delivered via master first and cherry-picked to the release branch.
+  </para>
+
+  <para>
+   Critical security fixes may by-pass the staging branches and be delivered directly to release branches such as <literal>master</literal> and <literal>release-*</literal>.
+  </para>
+ </section>
+ <section xml:id="submitting-changes-pull-request-template">
+  <title>Pull Request Template</title>
+
+  <para>
+   The pull request template helps determine what steps have been made for a contribution so far, and will help guide maintainers on the status of a change. The motivation section of the PR should include any extra details the title does not address and link any existing issues related to the pull request.
+  </para>
+
+  <para>
+   When a PR is created, it will be pre-populated with some checkboxes detailed below:
+  </para>
+
+  <section xml:id="submitting-changes-tested-with-sandbox">
+   <title>Tested using sandboxing</title>
+
+   <para>
+    When sandbox builds are enabled, Nix will setup an isolated environment for each build process. It is used to remove further hidden dependencies set by the build environment to improve reproducibility. This includes access to the network during the build outside of <function>fetch*</function> functions and files outside the Nix store. Depending on the operating system access to other resources are blocked as well (ex. inter process communication is isolated on Linux); see <link
+      xlink:href="https://nixos.org/nix/manual/#conf-sandbox">sandbox</link> in Nix manual for details.
+   </para>
+
+   <para>
+    Sandboxing is not enabled by default in Nix due to a small performance hit on each build. In pull requests for <link
+        xlink:href="https://github.com/NixOS/nixpkgs/">nixpkgs</link> people are asked to test builds with sandboxing enabled (see <literal>Tested using sandboxing</literal> in the pull request template) because in<link
+        xlink:href="https://nixos.org/hydra/">https://nixos.org/hydra/</link> sandboxing is also used.
+   </para>
+
+   <para>
+    Depending if you use NixOS or other platforms you can use one of the following methods to enable sandboxing <emphasis role="bold">before</emphasis> building the package:
+    <itemizedlist>
+     <listitem>
+      <para>
+       <emphasis role="bold">Globally enable sandboxing on NixOS</emphasis>: add the following to <filename>configuration.nix</filename>
+<screen>nix.useSandbox = true;</screen>
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       <emphasis role="bold">Globally enable sandboxing on non-NixOS platforms</emphasis>: add the following to: <filename>/etc/nix/nix.conf</filename>
+<screen>sandbox = true</screen>
+      </para>
+     </listitem>
+    </itemizedlist>
+   </para>
+  </section>
+
+  <section xml:id="submitting-changes-platform-diversity">
+   <title>Built on platform(s)</title>
+
+   <para>
+    Many Nix packages are designed to run on multiple platforms. As such, it's important to let the maintainer know which platforms your changes have been tested on. It's not always practical to test a change on all platforms, and is not required for a pull request to be merged. Only check the systems you tested the build on in this section.
+   </para>
+  </section>
+
+  <section xml:id="submitting-changes-nixos-tests">
+   <title>Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)</title>
+
+   <para>
+    Packages with automated tests are much more likely to be merged in a timely fashion because it doesn't require as much manual testing by the maintainer to verify the functionality of the package. If there are existing tests for the package, they should be run to verify your changes do not break the tests. Tests only apply to packages with NixOS modules defined and can only be run on Linux. For more details on writing and running tests, see the <link
+        xlink:href="https://nixos.org/nixos/manual/index.html#sec-nixos-tests">section in the NixOS manual</link>.
+   </para>
+  </section>
+
+  <section xml:id="submitting-changes-tested-compilation">
+   <title>Tested compilation of all pkgs that depend on this change using <command>nixpkgs-review</command></title>
+
+   <para>
+    If you are updating a package's version, you can use nixpkgs-review to make sure all packages that depend on the updated package still compile correctly. The <command>nixpkgs-review</command> utility can look for and build all dependencies either based on uncommited changes with the <literal>wip</literal> option or specifying a github pull request number.
+   </para>
+
+   <para>
+    review changes from pull request number 12345:
+    <screen>nix run nixpkgs.nixpkgs-review -c nixpkgs-review pr 12345</screen>
+   </para>
+
+   <para>
+    review uncommitted changes:
+    <screen>nix run nixpkgs.nixpkgs-review -c nixpkgs-review wip</screen>
+   </para>
+
+   <para>
+    review changes from last commit:
+    <screen>nix run nixpkgs.nixpkgs-review -c nixpkgs-review rev HEAD</screen>
+   </para>
+  </section>
+
+  <section xml:id="submitting-changes-tested-execution">
+   <title>Tested execution of all binary files (usually in <filename>./result/bin/</filename>)</title>
+
+   <para>
+    It's important to test any executables generated by a build when you change or create a package in nixpkgs. This can be done by looking in <filename>./result/bin</filename> and running any files in there, or at a minimum, the main executable for the package. For example, if you make a change to <package>texlive</package>, you probably would only check the binaries associated with the change you made rather than testing all of them.
+   </para>
+  </section>
+
+  <section xml:id="submitting-changes-contribution-standards">
+   <title>Meets Nixpkgs contribution standards</title>
+
+   <para>
+    The last checkbox is fits <link
+        xlink:href="https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md">CONTRIBUTING.md</link>. The contributing document has detailed information on standards the Nix community has for commit messages, reviews, licensing of contributions you make to the project, etc... Everyone should read and understand the standards the community has for contributing before submitting a pull request.
+   </para>
+  </section>
+ </section>
+ <section xml:id="submitting-changes-hotfixing-pull-requests">
+  <title>Hotfixing pull requests</title>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Make the appropriate changes in you branch.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Don't create additional commits, do
+     <itemizedlist>
+      <listitem>
+       <para>
+        <command>git rebase -i</command>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <command>git push --force</command> to your branch.
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+  </itemizedlist>
+ </section>
+ <section xml:id="submitting-changes-commit-policy">
+  <title>Commit policy</title>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Commits must be sufficiently tested before being merged, both for the master and staging branches.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Hydra builds for master and staging should not be used as testing platform, it's a build farm for changes that have been already tested.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     When changing the bootloader installation process, extra care must be taken. Grub installations cannot be rolled back, hence changes may break people's installations forever. For any non-trivial change to the bootloader please file a PR asking for review, especially from @edolstra.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <section xml:id="submitting-changes-master-branch">
+   <title>Master branch</title>
+   <para>
+    The <literal>master</literal> branch is the main development branch.
+    It should only see non-breaking commits that do not cause mass rebuilds.
+   </para>
+  </section>
+
+  <section xml:id="submitting-changes-staging-branch">
+   <title>Staging branch</title>
+   <para>
+    The <literal>staging</literal> branch is a development branch where mass-rebuilds go.
+    It should only see non-breaking mass-rebuild commits.
+    That means it is not to be used for testing, and changes must have been well tested already.
+    If the branch is already in a broken state, please refrain from adding extra new breakages.
+   </para>
+  </section>
+
+  <section xml:id="submitting-changes-staging-next-branch">
+   <title>Staging-next branch</title>
+   <para>
+    The <literal>staging-next</literal> branch is for stabilizing mass-rebuilds submitted to the <literal>staging</literal> branch prior to merging them into <literal>master</literal>.
+    Mass-rebuilds should go via the <literal>staging</literal> branch.
+    It should only see non-breaking commits that are fixing issues blocking it from being merged into the <literal>master </literal> branch.
+   </para>
+   <para>
+    If the branch is already in a broken state, please refrain from adding extra new breakages. Stabilize it for a few days and then merge into master.
+   </para>
+  </section>
+
+  <section xml:id="submitting-changes-stable-release-branches">
+   <title>Stable release branches</title>
+
+   <itemizedlist>
+    <listitem>
+     <para>
+      If you're cherry-picking a commit to a stable release branch (“backporting”), always use <command>git cherry-pick -xe</command> and ensure the message contains a clear description about why this needs to be included in the stable branch.
+     </para>
+     <para>
+      An example of a cherry-picked commit would look like this:
+     </para>
+<screen>
+nixos: Refactor the world.
+
+The original commit message describing the reason why the world was torn apart.
+
+(cherry picked from commit abcdef)
+Reason: I just had a gut feeling that this would also be wanted by people from
+the stone age.
+</screen>
+    </listitem>
+   </itemizedlist>
+  </section>
+ </section>
+</chapter>

third_party/nixpkgs/doc/default.nix

@@ -0,0 +1,28 @@
+{ pkgs ? (import ./.. { }), nixpkgs ? { }}:
+let
+  lib = pkgs.lib;
+  doc-support = import ./doc-support { inherit pkgs nixpkgs; };
+in pkgs.stdenv.mkDerivation {
+  name = "nixpkgs-manual";
+
+  buildInputs = with pkgs; [ pandoc libxml2 libxslt zip jing  xmlformat ];
+
+  src = ./.;
+
+  postPatch = ''
+    ln -s ${doc-support} ./doc-support/result
+  '';
+
+  installPhase = ''
+    dest="$out/share/doc/nixpkgs"
+    mkdir -p "$(dirname "$dest")"
+    mv out/html "$dest"
+    mv "$dest/index.html" "$dest/manual.html"
+
+    mv out/epub/manual.epub "$dest/nixpkgs-manual.epub"
+
+    mkdir -p $out/nix-support/
+    echo "doc manual $dest manual.html" >> $out/nix-support/hydra-build-products
+    echo "doc manual $dest nixpkgs-manual.epub" >> $out/nix-support/hydra-build-products
+  '';
+}

third_party/nixpkgs/doc/doc-support/default.nix

@@ -0,0 +1,45 @@
+{ pkgs ? (import ../.. {}), nixpkgs ? { }}:
+let
+  locationsXml = import ./lib-function-locations.nix { inherit pkgs nixpkgs; };
+  functionDocs = import ./lib-function-docs.nix { inherit locationsXml pkgs; };
+  version = pkgs.lib.version;
+
+  epub-xsl = pkgs.writeText "epub.xsl" ''
+    <?xml version='1.0'?>
+    <xsl:stylesheet
+      xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+      version="1.0">
+      <xsl:import href="${pkgs.docbook_xsl_ns}/xml/xsl/docbook/epub/docbook.xsl" />
+      <xsl:import href="${./parameters.xml}"/>
+    </xsl:stylesheet>
+  '';
+
+  xhtml-xsl = pkgs.writeText "xhtml.xsl" ''
+    <?xml version='1.0'?>
+    <xsl:stylesheet
+      xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+      version="1.0">
+      <xsl:import href="${pkgs.docbook_xsl_ns}/xml/xsl/docbook/xhtml/docbook.xsl" />
+      <xsl:import href="${./parameters.xml}"/>
+    </xsl:stylesheet>
+  '';
+in pkgs.runCommand "doc-support" {}
+''
+  mkdir result
+  (
+    cd result
+    ln -s ${locationsXml} ./function-locations.xml
+    ln -s ${functionDocs} ./function-docs
+
+    ln -s ${pkgs.docbook5}/xml/rng/docbook/docbook.rng ./docbook.rng
+    ln -s ${pkgs.docbook_xsl_ns}/xml/xsl ./xsl
+    ln -s ${epub-xsl} ./epub.xsl
+    ln -s ${xhtml-xsl} ./xhtml.xsl
+
+    ln -s ${../../nixos/doc/xmlformat.conf} ./xmlformat.conf
+    ln -s ${pkgs.documentation-highlighter} ./highlightjs
+
+    echo -n "${version}" > ./version
+  )
+  mv result $out
+''

third_party/nixpkgs/doc/doc-support/lib-function-docs.nix

@@ -0,0 +1,26 @@
+# Generates the documentation for library functons via nixdoc. To add
+# another library function file to this list, the include list in the
+# file `doc/functions/library.xml` must also be updated.
+
+{ pkgs ? import ./.. {}, locationsXml }:
+
+with pkgs; stdenv.mkDerivation {
+  name = "nixpkgs-lib-docs";
+  src = ./../../lib;
+
+  buildInputs = [ nixdoc ];
+  installPhase = ''
+    function docgen {
+      nixdoc -c "$1" -d "$2" -f "../lib/$1.nix"  > "$out/$1.xml"
+    }
+
+    mkdir -p $out
+    ln -s ${locationsXml} $out/locations.xml
+
+    docgen strings 'String manipulation functions'
+    docgen trivial 'Miscellaneous functions'
+    docgen lists 'List manipulation functions'
+    docgen debug 'Debugging functions'
+    docgen options 'NixOS / nixpkgs option handling'
+  '';
+}

third_party/nixpkgs/doc/doc-support/lib-function-locations.nix

@@ -0,0 +1,85 @@
+{ pkgs ? (import ./.. { }), nixpkgs ? { }}:
+let
+  revision = pkgs.lib.trivial.revisionWithDefault (nixpkgs.revision or "master");
+
+  libDefPos = set:
+    builtins.map
+      (name: {
+        name = name;
+        location = builtins.unsafeGetAttrPos name set;
+      })
+      (builtins.attrNames set);
+
+  libset = toplib:
+    builtins.map
+      (subsetname: {
+        subsetname = subsetname;
+        functions = libDefPos toplib.${subsetname};
+      })
+      (builtins.filter
+        (name: builtins.isAttrs toplib.${name})
+        (builtins.attrNames toplib));
+
+  nixpkgsLib = pkgs.lib;
+
+  flattenedLibSubset = { subsetname, functions }:
+  builtins.map
+    (fn: {
+      name = "lib.${subsetname}.${fn.name}";
+      value = fn.location;
+    })
+    functions;
+
+  locatedlibsets = libs: builtins.map flattenedLibSubset (libset libs);
+  removeFilenamePrefix = prefix: filename:
+    let
+    prefixLen = (builtins.stringLength prefix) + 1; # +1 to remove the leading /
+      filenameLen = builtins.stringLength filename;
+      substr = builtins.substring prefixLen filenameLen filename;
+      in substr;
+
+  removeNixpkgs = removeFilenamePrefix (builtins.toString pkgs.path);
+
+  liblocations =
+    builtins.filter
+      (elem: elem.value != null)
+      (nixpkgsLib.lists.flatten
+        (locatedlibsets nixpkgsLib));
+
+  fnLocationRelative = { name, value }:
+    {
+      inherit name;
+      value = value // { file = removeNixpkgs value.file; };
+    };
+
+  relativeLocs = (builtins.map fnLocationRelative liblocations);
+  sanitizeId = builtins.replaceStrings
+    [ "'"      ]
+    [ "-prime" ];
+
+  urlPrefix = "https://github.com/NixOS/nixpkgs/blob/${revision}";
+  xmlstrings = (nixpkgsLib.strings.concatMapStrings
+      ({ name, value }:
+      ''
+      <section><title>${name}</title>
+        <para xml:id="${sanitizeId name}">
+        Located at
+        <link
+          xlink:href="${urlPrefix}/${value.file}#L${builtins.toString value.line}">${value.file}:${builtins.toString value.line}</link>
+        in  <literal>&lt;nixpkgs&gt;</literal>.
+        </para>
+        </section>
+      '')
+      relativeLocs);
+
+in pkgs.writeText
+    "locations.xml"
+    ''
+    <section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         version="5">
+         <title>All the locations for every lib function</title>
+         <para>This file is only for inclusion by other files.</para>
+         ${xmlstrings}
+    </section>
+    ''

third_party/nixpkgs/doc/doc-support/parameters.xml

@@ -0,0 +1,14 @@
+<?xml version='1.0'?>
+<xsl:stylesheet
+    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+    version="1.0">
+ <xsl:param name="section.autolabel" select="1" />
+ <xsl:param name="section.label.includes.component.label" select="1" />
+ <xsl:param name="html.stylesheet" select="'style.css overrides.css highlightjs/mono-blue.css'" />
+ <xsl:param name="html.script" select="'./highlightjs/highlight.pack.js ./highlightjs/loader.js'" />
+ <xsl:param name="xref.with.number.and.title" select="1" />
+ <xsl:param name="use.id.as.filename" select="1" />
+ <xsl:param name="toc.section.depth" select="0" />
+ <xsl:param name="admon.style" select="''" />
+ <xsl:param name="callout.graphics.extension" select="'.svg'" />
+</xsl:stylesheet>

third_party/nixpkgs/doc/functions.xml

@@ -0,0 +1,14 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-functions">
+ <title>Functions reference</title>
+ <para>
+  The nixpkgs repository has several utility functions to manipulate Nix expressions.
+ </para>
+ <xi:include href="functions/library.xml" />
+ <xi:include href="functions/generators.xml" />
+ <xi:include href="functions/debug.xml" />
+ <xi:include href="functions/prefer-remote-fetch.xml" />
+ <xi:include href="functions/nix-gitignore.xml" />
+</chapter>

third_party/nixpkgs/doc/functions/debug.xml

@@ -0,0 +1,14 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-debug">
+ <title>Debugging Nix Expressions</title>
+
+ <para>
+  Nix is a unityped, dynamic language, this means every value can potentially appear anywhere. Since it is also non-strict, evaluation order and what ultimately is evaluated might surprise you. Therefore it is important to be able to debug nix expressions.
+ </para>
+
+ <para>
+  In the <literal>lib/debug.nix</literal> file you will find a number of functions that help (pretty-)printing values while evaluation is runnnig. You can even specify how deep these values should be printed recursively, and transform them on the fly. Please consult the docstrings in <literal>lib/debug.nix</literal> for usage information.
+ </para>
+</section>

third_party/nixpkgs/doc/functions/generators.xml

@@ -0,0 +1,74 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-generators">
+ <title>Generators</title>
+
+ <para>
+  Generators are functions that create file formats from nix data structures, e. g. for configuration files. There are generators available for: <literal>INI</literal>, <literal>JSON</literal> and <literal>YAML</literal>
+ </para>
+
+ <para>
+  All generators follow a similar call interface: <code>generatorName configFunctions data</code>, where <literal>configFunctions</literal> is an attrset of user-defined functions that format nested parts of the content. They each have common defaults, so often they do not need to be set manually. An example is <code>mkSectionName ? (name: libStr.escape [ "[" "]" ] name)</code> from the <literal>INI</literal> generator. It receives the name of a section and sanitizes it. The default <literal>mkSectionName</literal> escapes <literal>[</literal> and <literal>]</literal> with a backslash.
+ </para>
+
+ <para>
+  Generators can be fine-tuned to produce exactly the file format required by your application/service. One example is an INI-file format which uses <literal>: </literal> as separator, the strings <literal>"yes"</literal>/<literal>"no"</literal> as boolean values and requires all string values to be quoted:
+ </para>
+
+<programlisting>
+with lib;
+let
+  customToINI = generators.toINI {
+    # specifies how to format a key/value pair
+    mkKeyValue = generators.mkKeyValueDefault {
+      # specifies the generated string for a subset of nix values
+      mkValueString = v:
+             if v == true then ''"yes"''
+        else if v == false then ''"no"''
+        else if isString v then ''"${v}"''
+        # and delegats all other values to the default generator
+        else generators.mkValueStringDefault {} v;
+    } ":";
+  };
+
+# the INI file can now be given as plain old nix values
+in customToINI {
+  main = {
+    pushinfo = true;
+    autopush = false;
+    host = "localhost";
+    port = 42;
+  };
+  mergetool = {
+    merge = "diff3";
+  };
+}
+</programlisting>
+
+ <para>
+  This will produce the following INI file as nix string:
+ </para>
+
+<programlisting>
+[main]
+autopush:"no"
+host:"localhost"
+port:42
+pushinfo:"yes"
+str\:ange:"very::strange"
+
+[mergetool]
+merge:"diff3"
+</programlisting>
+
+ <note>
+  <para>
+   Nix store paths can be converted to strings by enclosing a derivation attribute like so: <code>"${drv}"</code>.
+  </para>
+ </note>
+
+ <para>
+  Detailed documentation for each generator can be found in <literal>lib/generators.nix</literal>.
+ </para>
+</section>

third_party/nixpkgs/doc/functions/library.xml

@@ -0,0 +1,28 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-functions-library">
+ <title>Nixpkgs Library Functions</title>
+
+ <para>
+  Nixpkgs provides a standard library at <varname>pkgs.lib</varname>, or through <code>import &lt;nixpkgs/lib&gt;</code>.
+ </para>
+
+ <xi:include href="./library/asserts.xml" />
+
+ <xi:include href="./library/attrsets.xml" />
+
+<!-- These docs are generated via nixdoc. To add another generated
+      library function file to this list, the file
+      `lib-function-docs.nix` must also be updated. -->
+
+ <xi:include href="./library/generated/strings.xml" />
+
+ <xi:include href="./library/generated/trivial.xml" />
+
+ <xi:include href="./library/generated/lists.xml" />
+
+ <xi:include href="./library/generated/debug.xml" />
+
+ <xi:include href="./library/generated/options.xml" />
+</section>

third_party/nixpkgs/doc/functions/library/asserts.xml

@@ -0,0 +1,112 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-functions-library-asserts">
+ <title>Assert functions</title>
+
+ <section xml:id="function-library-lib.asserts.assertMsg">
+  <title><function>lib.asserts.assertMsg</function></title>
+
+  <subtitle><literal>assertMsg :: Bool -> String -> Bool</literal>
+  </subtitle>
+
+  <xi:include href="./locations.xml" xpointer="lib.asserts.assertMsg" />
+
+  <para>
+   Print a trace message if <literal>pred</literal> is false.
+  </para>
+
+  <para>
+   Intended to be used to augment asserts with helpful error messages.
+  </para>
+
+  <variablelist>
+   <varlistentry>
+    <term>
+     <varname>pred</varname>
+    </term>
+    <listitem>
+     <para>
+      Condition under which the <varname>msg</varname> should <emphasis>not</emphasis> be printed.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>msg</varname>
+    </term>
+    <listitem>
+     <para>
+      Message to print.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+
+  <example xml:id="function-library-lib.asserts.assertMsg-example-false">
+   <title>Printing when the predicate is false</title>
+<programlisting><![CDATA[
+assert lib.asserts.assertMsg ("foo" == "bar") "foo is not bar, silly"
+stderr> trace: foo is not bar, silly
+stderr> assert failed
+]]></programlisting>
+  </example>
+ </section>
+
+ <section xml:id="function-library-lib.asserts.assertOneOf">
+  <title><function>lib.asserts.assertOneOf</function></title>
+
+  <subtitle><literal>assertOneOf :: String -> String ->
+      StringList -> Bool</literal>
+  </subtitle>
+
+  <xi:include href="./locations.xml" xpointer="lib.asserts.assertOneOf" />
+
+  <para>
+   Specialized <function>asserts.assertMsg</function> for checking if <varname>val</varname> is one of the elements of <varname>xs</varname>. Useful for checking enums.
+  </para>
+
+  <variablelist>
+   <varlistentry>
+    <term>
+     <varname>name</varname>
+    </term>
+    <listitem>
+     <para>
+      The name of the variable the user entered <varname>val</varname> into, for inclusion in the error message.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>val</varname>
+    </term>
+    <listitem>
+     <para>
+      The value of what the user provided, to be compared against the values in <varname>xs</varname>.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>xs</varname>
+    </term>
+    <listitem>
+     <para>
+      The list of valid values.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+
+  <example xml:id="function-library-lib.asserts.assertOneOf-example">
+   <title>Ensuring a user provided a possible value</title>
+<programlisting><![CDATA[
+let sslLibrary = "bearssl";
+in lib.asserts.assertOneOf "sslLibrary" sslLibrary [ "openssl" "bearssl" ];
+=> false
+stderr> trace: sslLibrary must be one of "openssl", "libressl", but is: "bearssl"
+        ]]></programlisting>
+  </example>
+ </section>
+</section>

third_party/nixpkgs/doc/functions/nix-gitignore.xml

@@ -0,0 +1,70 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-pkgs-nix-gitignore">
+ <title>pkgs.nix-gitignore</title>
+
+ <para>
+  <function>pkgs.nix-gitignore</function> is a function that acts similarly to <literal>builtins.filterSource</literal> but also allows filtering with the help of the gitignore format.
+ </para>
+
+ <section xml:id="sec-pkgs-nix-gitignore-usage">
+  <title>Usage</title>
+
+  <para>
+   <literal>pkgs.nix-gitignore</literal> exports a number of functions, but you'll most likely need either <literal>gitignoreSource</literal> or <literal>gitignoreSourcePure</literal>. As their first argument, they both accept either 1. a file with gitignore lines or 2. a string with gitignore lines, or 3. a list of either of the two. They will be concatenated into a single big string.
+  </para>
+
+<programlisting><![CDATA[
+{ pkgs ? import <nixpkgs> {} }:
+
+ nix-gitignore.gitignoreSource [] ./source
+     # Simplest version
+
+ nix-gitignore.gitignoreSource "supplemental-ignores\n" ./source
+     # This one reads the ./source/.gitignore and concats the auxiliary ignores
+
+ nix-gitignore.gitignoreSourcePure "ignore-this\nignore-that\n" ./source
+     # Use this string as gitignore, don't read ./source/.gitignore.
+
+ nix-gitignore.gitignoreSourcePure ["ignore-this\nignore-that\n", ~/.gitignore] ./source
+     # It also accepts a list (of strings and paths) that will be concatenated
+     # once the paths are turned to strings via readFile.
+  ]]></programlisting>
+
+  <para>
+   These functions are derived from the <literal>Filter</literal> functions by setting the first filter argument to <literal>(_: _: true)</literal>:
+  </para>
+
+<programlisting><![CDATA[
+gitignoreSourcePure = gitignoreFilterSourcePure (_: _: true);
+gitignoreSource = gitignoreFilterSource (_: _: true);
+  ]]></programlisting>
+
+  <para>
+   Those filter functions accept the same arguments the <literal>builtins.filterSource</literal> function would pass to its filters, thus <literal>fn: gitignoreFilterSourcePure fn ""</literal> should be extensionally equivalent to <literal>filterSource</literal>. The file is blacklisted iff it's blacklisted by either your filter or the gitignoreFilter.
+  </para>
+
+  <para>
+   If you want to make your own filter from scratch, you may use
+  </para>
+
+<programlisting><![CDATA[
+gitignoreFilter = ign: root: filterPattern (gitignoreToPatterns ign) root;
+  ]]></programlisting>
+ </section>
+
+ <section xml:id="sec-pkgs-nix-gitignore-usage-recursive">
+  <title>gitignore files in subdirectories</title>
+
+  <para>
+   If you wish to use a filter that would search for .gitignore files in subdirectories, just like git does by default, use this function:
+  </para>
+
+<programlisting><![CDATA[
+gitignoreFilterRecursiveSource = filter: patterns: root:
+# OR
+gitignoreRecursiveSource = gitignoreFilterSourcePure (_: _: true);
+  ]]></programlisting>
+ </section>
+</section>

third_party/nixpkgs/doc/functions/prefer-remote-fetch.xml

@@ -0,0 +1,21 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/xinclude"
+         xml:id="sec-prefer-remote-fetch">
+ <title>prefer-remote-fetch overlay</title>
+
+ <para>
+  <function>prefer-remote-fetch</function> is an overlay that download sources on remote builder. This is useful when the evaluating machine has a slow upload while the builder can fetch faster directly from the source. To use it, put the following snippet as a new overlay:
+<programlisting>
+self: super:
+  (super.prefer-remote-fetch self super)
+</programlisting>
+  A full configuration example for that sets the overlay up for your own account, could look like this
+<screen>
+<prompt>$ </prompt>mkdir ~/.config/nixpkgs/overlays/
+<prompt>$ </prompt>cat &gt; ~/.config/nixpkgs/overlays/prefer-remote-fetch.nix &lt;&lt;EOF
+  self: super: super.prefer-remote-fetch self super
+EOF
+</screen>
+ </para>
+</section>

third_party/nixpkgs/doc/languages-frameworks/android.section.md

@@ -0,0 +1,239 @@
+---
+title: Android
+author: Sander van der Burg
+date: 2018-11-18
+---
+# Android
+
+The Android build environment provides three major features and a number of
+supporting features.
+
+Deploying an Android SDK installation with plugins
+--------------------------------------------------
+The first use case is deploying the SDK with a desired set of plugins or subsets
+of an SDK.
+
+```nix
+with import <nixpkgs> {};
+
+let
+  androidComposition = androidenv.composeAndroidPackages {
+    toolsVersion = "25.2.5";
+    platformToolsVersion = "27.0.1";
+    buildToolsVersions = [ "27.0.3" ];
+    includeEmulator = false;
+    emulatorVersion = "27.2.0";
+    platformVersions = [ "24" ];
+    includeSources = false;
+    includeDocs = false;
+    includeSystemImages = false;
+    systemImageTypes = [ "default" ];
+    abiVersions = [ "armeabi-v7a" ];
+    lldbVersions = [ "2.0.2558144" ];
+    cmakeVersions = [ "3.6.4111459" ];
+    includeNDK = false;
+    ndkVersion = "16.1.4479499";
+    useGoogleAPIs = false;
+    useGoogleTVAddOns = false;
+    includeExtras = [
+      "extras;google;gcm"
+    ];
+  };
+in
+androidComposition.androidsdk
+```
+
+The above function invocation states that we want an Android SDK with the above
+specified plugin versions. By default, most plugins are disabled. Notable
+exceptions are the tools, platform-tools and build-tools sub packages.
+
+The following parameters are supported:
+
+* `toolsVersion`, specifies the version of the tools package to use
+* `platformsToolsVersion` specifies the version of the `platform-tools` plugin
+* `buildToolsVersion` specifies the versions of the `build-tools` plugins to
+  use.
+* `includeEmulator` specifies whether to deploy the emulator package (`false`
+  by default). When enabled, the version of the emulator to deploy can be
+  specified by setting the `emulatorVersion` parameter.
+* `includeDocs` specifies whether the documentation catalog should be included.
+* `lldbVersions` specifies what LLDB versions should be deployed.
+* `cmakeVersions` specifies which CMake versions should be deployed.
+* `includeNDK` specifies that the Android NDK bundle should be included.
+  Defaults to: `false`.
+* `ndkVersion` specifies the NDK version that we want to use.
+* `includeExtras` is an array of identifier strings referring to arbitrary
+  add-on packages that should be installed.
+* `platformVersions` specifies which platform SDK versions should be included.
+
+For each platform version that has been specified, we can apply the following
+options:
+
+* `includeSystemImages` specifies whether a system image for each platform SDK
+  should be included.
+* `includeSources` specifies whether the sources for each SDK version should be
+  included.
+* `useGoogleAPIs` specifies that for each selected platform version the
+  Google API should be included.
+* `useGoogleTVAddOns` specifies that for each selected platform version the
+  Google TV add-on should be included.
+
+For each requested system image we can specify the following options:
+
+* `systemImageTypes` specifies what kind of system images should be included.
+  Defaults to: `default`.
+* `abiVersions` specifies what kind of ABI version of each system image should
+  be included. Defaults to: `armeabi-v7a`.
+
+Most of the function arguments have reasonable default settings.
+
+When building the above expression with:
+
+```bash
+$ nix-build
+```
+
+The Android SDK gets deployed with all desired plugin versions.
+
+We can also deploy subsets of the Android SDK. For example, to only the
+`platform-tools` package, you can evaluate the following expression:
+
+```nix
+with import <nixpkgs> {};
+
+let
+  androidComposition = androidenv.composeAndroidPackages {
+    # ...
+  };
+in
+androidComposition.platform-tools
+```
+
+Using predefine Android package compositions
+--------------------------------------------
+In addition to composing an Android package set manually, it is also possible
+to use a predefined composition that contains all basic packages for a specific
+Android version, such as version 9.0 (API-level 28).
+
+The following Nix expression can be used to deploy the entire SDK with all basic
+plugins:
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.androidPkgs_9_0.androidsdk
+```
+
+It is also possible to use one plugin only:
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.androidPkgs_9_0.platform-tools
+```
+
+Building an Android application
+-------------------------------
+In addition to the SDK, it is also possible to build an Ant-based Android
+project and automatically deploy all the Android plugins that a project
+requires.
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.buildApp {
+  name = "MyAndroidApp";
+  src = ./myappsources;
+  release = true;
+
+  # If release is set to true, you need to specify the following parameters
+  keyStore = ./keystore;
+  keyAlias = "myfirstapp";
+  keyStorePassword = "mykeystore";
+  keyAliasPassword = "myfirstapp";
+
+  # Any Android SDK parameters that install all the relevant plugins that a
+  # build requires
+  platformVersions = [ "24" ];
+
+  # When we include the NDK, then ndk-build is invoked before Ant gets invoked
+  includeNDK = true;
+}
+```
+
+Aside from the app-specific build parameters (`name`, `src`, `release` and
+keystore parameters), the `buildApp {}` function supports all the function
+parameters that the SDK composition function (the function shown in the
+previous section) supports.
+
+This build function is particularly useful when it is desired to use
+[Hydra](http://nixos.org/hydra): the Nix-based continuous integration solution
+to build Android apps. An Android APK gets exposed as a build product and can be
+installed on any Android device with a web browser by navigating to the build
+result page.
+
+Spawning emulator instances
+---------------------------
+For testing purposes, it can also be quite convenient to automatically generate
+scripts that spawn emulator instances with all desired configuration settings.
+
+An emulator spawn script can be configured by invoking the `emulateApp {}`
+function:
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.emulateApp {
+  name = "emulate-MyAndroidApp";
+  platformVersion = "28";
+  abiVersion = "x86"; # armeabi-v7a, mips, x86_64
+  systemImageType = "google_apis_playstore";
+}
+```
+
+It is also possible to specify an APK to deploy inside the emulator
+and the package and activity names to launch it:
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.emulateApp {
+  name = "emulate-MyAndroidApp";
+  platformVersion = "24";
+  abiVersion = "armeabi-v7a"; # mips, x86, x86_64
+  systemImageType = "default";
+  useGoogleAPIs = false;
+  app = ./MyApp.apk;
+  package = "MyApp";
+  activity = "MainActivity";
+}
+```
+
+In addition to prebuilt APKs, you can also bind the APK parameter to a
+`buildApp {}` function invocation shown in the previous example.
+
+Querying the available versions of each plugin
+----------------------------------------------
+When using any of the previously shown functions, it may be a bit inconvenient
+to find out what options are supported, since the Android SDK provides many
+plugins.
+
+A shell script in the `pkgs/development/mobile/androidenv/` sub directory can be used to retrieve all
+possible options:
+
+```bash
+sh ./querypackages.sh packages build-tools
+```
+
+The above command-line instruction queries all build-tools versions in the
+generated `packages.nix` expression.
+
+Updating the generated expressions
+----------------------------------
+Most of the Nix expressions are generated from XML files that the Android
+package manager uses. To update the expressions run the `generate.sh` script
+that is stored in the `pkgs/development/mobile/androidenv/` sub directory:
+
+```bash
+./generate.sh
+```

third_party/nixpkgs/doc/languages-frameworks/beam.xml

@@ -0,0 +1,159 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-beam">
+ <title>BEAM Languages (Erlang, Elixir &amp; LFE)</title>
+
+ <section xml:id="beam-introduction">
+  <title>Introduction</title>
+
+  <para>
+   In this document and related Nix expressions, we use the term, <emphasis>BEAM</emphasis>, to describe the environment. BEAM is the name of the Erlang Virtual Machine and, as far as we're concerned, from a packaging perspective, all languages that run on the BEAM are interchangeable. That which varies, like the build system, is transparent to users of any given BEAM package, so we make no distinction.
+  </para>
+ </section>
+
+ <section xml:id="beam-structure">
+  <title>Structure</title>
+
+  <para>
+   All BEAM-related expressions are available via the top-level <literal>beam</literal> attribute, which includes:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <literal>interpreters</literal>: a set of compilers running on the BEAM, including multiple Erlang/OTP versions (<literal>beam.interpreters.erlangR19</literal>, etc), Elixir (<literal>beam.interpreters.elixir</literal>) and LFE (<literal>beam.interpreters.lfe</literal>).
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     <literal>packages</literal>: a set of package builders (Mix and rebar3), each compiled with a specific Erlang/OTP version, e.g. <literal>beam.packages.erlangR19</literal>.
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   The default Erlang compiler, defined by <literal>beam.interpreters.erlang</literal>, is aliased as <literal>erlang</literal>. The default BEAM package set is defined by <literal>beam.packages.erlang</literal> and aliased at the top level as <literal>beamPackages</literal>.
+  </para>
+
+  <para>
+   To create a package builder built with a custom Erlang version, use the lambda, <literal>beam.packagesWith</literal>, which accepts an Erlang/OTP derivation and produces a package builder similar to <literal>beam.packages.erlang</literal>.
+  </para>
+
+  <para>
+   Many Erlang/OTP distributions available in <literal>beam.interpreters</literal> have versions with ODBC and/or Java enabled or without wx (no observer support). For example, there's <literal>beam.interpreters.erlangR22_odbc_javac</literal>, which corresponds to <literal>beam.interpreters.erlangR22</literal> and <literal>beam.interpreters.erlangR22_nox</literal>, which corresponds to <literal>beam.interpreters.erlangR22</literal>.
+  </para>
+ </section>
+
+ <section xml:id="build-tools">
+  <title>Build Tools</title>
+
+  <section xml:id="build-tools-rebar3">
+   <title>Rebar3</title>
+
+   <para>
+    We provide a version of Rebar3, under <literal>rebar3</literal>. We also provide a helper to fetch Rebar3 dependencies from a lockfile under <literal>fetchRebar3Deps</literal>.
+   </para>
+  </section>
+
+  <section xml:id="build-tools-other">
+   <title>Mix &amp; Erlang.mk</title>
+
+   <para>
+    Both Mix and Erlang.mk work exactly as expected. There is a bootstrap process that needs to be run for both, however, which is supported by the <literal>buildMix</literal> and <literal>buildErlangMk</literal> derivations, respectively.
+   </para>
+  </section>
+ </section>
+
+ <section xml:id="how-to-install-beam-packages">
+  <title>How to Install BEAM Packages</title>
+
+  <para>
+   BEAM builders are not registered at the top level, simply because they are not relevant to the vast majority of Nix users. 
+   To install any of those builders into your profile, refer to them by their attribute path <literal>beamPackages.rebar3</literal>:
+  </para>
+
+  <screen>
+  <prompt>$ </prompt>nix-env -f &quot;&lt;nixpkgs&gt;&quot; -iA beamPackages.rebar3
+  </screen>
+</section>
+
+ <section xml:id="packaging-beam-applications">
+  <title>Packaging BEAM Applications</title>
+
+  <section  xml:id="packaging-erlang-applications">
+   <title>Erlang Applications</title>
+
+   <section xml:id="rebar3-packages">
+    <title>Rebar3 Packages</title>
+
+    <para>
+     The Nix function, <literal>buildRebar3</literal>, defined in <literal>beam.packages.erlang.buildRebar3</literal> and aliased at the top level, can be used to build a derivation that understands how to build a Rebar3 project.
+    </para>
+
+    <para>
+     If a package needs to compile native code via Rebar3's port compilation mechanism, add <literal>compilePort = true;</literal> to the derivation.
+    </para>
+   </section>
+
+   <section xml:id="erlang-mk-packages">
+    <title>Erlang.mk Packages</title>
+
+    <para>
+     Erlang.mk functions similarly to Rebar3, except we use <literal>buildErlangMk</literal> instead of <literal>buildRebar3</literal>.
+    </para>
+
+   </section>
+
+   <section xml:id="mix-packages">
+    <title>Mix Packages</title>
+
+    <para>
+     Mix functions similarly to Rebar3, except we use <literal>buildMix</literal> instead of <literal>buildRebar3</literal>.
+    </para>
+
+    <para>
+     Alternatively, we can use <literal>buildHex</literal> as a shortcut:
+    </para>
+   </section>
+  </section>
+ </section>
+
+ <section xml:id="how-to-develop">
+  <title>How to Develop</title>
+
+  <section xml:id="creating-a-shell">
+   <title>Creating a Shell</title>
+
+  <para>
+    Usually, we need to create a <literal>shell.nix</literal> file and do our development inside of the environment specified therein. Just install your version of erlang and other interpreter, and then user your normal build tools.
+    As an example with elixir:
+  </para>
+
+<programlisting>
+{ pkgs ? import &quot;&lt;nixpkgs&quot;&gt; {} }:
+
+with pkgs;
+
+let
+
+  elixir = beam.packages.erlangR22.elixir_1_9;
+
+in
+mkShell {
+  buildInputs = [ elixir ];
+
+  ERL_INCLUDE_PATH="${erlang}/lib/erlang/usr/include";
+}
+</programlisting>
+
+   <section xml:id="building-in-a-shell">
+    <title>Building in a Shell (for Mix Projects)</title>
+
+    <para>
+     Using a <literal>shell.nix</literal> as described (see <xref
+      linkend="creating-a-shell"/>) should just work.
+    </para>
+   </section>
+  </section>
+ </section>
+</section>

third_party/nixpkgs/doc/languages-frameworks/bower.xml

@@ -0,0 +1,196 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-bower">
+ <title>Bower</title>
+
+ <para>
+  <link xlink:href="http://bower.io">Bower</link> is a package manager for web site front-end components. Bower packages (comprising of build artefacts and sometimes sources) are stored in <command>git</command> repositories, typically on Github. The package registry is run by the Bower team with package metadata coming from the <filename>bower.json</filename> file within each package.
+ </para>
+
+ <para>
+  The end result of running Bower is a <filename>bower_components</filename> directory which can be included in the web app's build process.
+ </para>
+
+ <para>
+  Bower can be run interactively, by installing <varname>nodePackages.bower</varname>. More interestingly, the Bower components can be declared in a Nix derivation, with the help of <varname>nodePackages.bower2nix</varname>.
+ </para>
+
+ <section xml:id="ssec-bower2nix-usage">
+  <title><command>bower2nix</command> usage</title>
+
+  <para>
+   Suppose you have a <filename>bower.json</filename> with the following contents:
+   <example xml:id="ex-bowerJson">
+    <title><filename>bower.json</filename></title>
+<programlisting language="json">
+<![CDATA[{
+  "name": "my-web-app",
+  "dependencies": {
+    "angular": "~1.5.0",
+    "bootstrap": "~3.3.6"
+  }
+}]]>
+</programlisting>
+   </example>
+  </para>
+
+  <para>
+   Running <command>bower2nix</command> will produce something like the following output:
+<programlisting language="nix">
+<![CDATA[{ fetchbower, buildEnv }:
+buildEnv { name = "bower-env"; ignoreCollisions = true; paths = [
+  (fetchbower "angular" "1.5.3" "~1.5.0" "1749xb0firxdra4rzadm4q9x90v6pzkbd7xmcyjk6qfza09ykk9y")
+  (fetchbower "bootstrap" "3.3.6" "~3.3.6" "1vvqlpbfcy0k5pncfjaiskj3y6scwifxygfqnw393sjfxiviwmbv")
+  (fetchbower "jquery" "2.2.2" "1.9.1 - 2" "10sp5h98sqwk90y4k6hbdviwqzvzwqf47r3r51pakch5ii2y7js1")
+]; }]]>
+</programlisting>
+  </para>
+
+  <para>
+   Using the <command>bower2nix</command> command line arguments, the output can be redirected to a file. A name like <filename>bower-packages.nix</filename> would be fine.
+  </para>
+
+  <para>
+   The resulting derivation is a union of all the downloaded Bower packages (and their dependencies). To use it, they still need to be linked together by Bower, which is where <varname>buildBowerComponents</varname> is useful.
+  </para>
+ </section>
+
+ <section xml:id="ssec-build-bower-components">
+  <title><varname>buildBowerComponents</varname> function</title>
+
+  <para>
+   The function is implemented in <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/bower-modules/generic/default.nix"> <filename>pkgs/development/bower-modules/generic/default.nix</filename></link>. Example usage:
+   <example xml:id="ex-buildBowerComponents">
+    <title>buildBowerComponents</title>
+<programlisting language="nix">
+bowerComponents = buildBowerComponents {
+  name = "my-web-app";
+  generated = ./bower-packages.nix; <co xml:id="ex-buildBowerComponents-1" />
+  src = myWebApp; <co xml:id="ex-buildBowerComponents-2" />
+};
+</programlisting>
+   </example>
+  </para>
+
+  <para>
+   In <xref linkend="ex-buildBowerComponents" />, the following arguments are of special significance to the function:
+   <calloutlist>
+    <callout arearefs="ex-buildBowerComponents-1">
+     <para>
+      <varname>generated</varname> specifies the file which was created by <command>bower2nix</command>.
+     </para>
+    </callout>
+    <callout arearefs="ex-buildBowerComponents-2">
+     <para>
+      <varname>src</varname> is your project's sources. It needs to contain a <filename>bower.json</filename> file.
+     </para>
+    </callout>
+   </calloutlist>
+  </para>
+
+  <para>
+   <varname>buildBowerComponents</varname> will run Bower to link together the output of <command>bower2nix</command>, resulting in a <filename>bower_components</filename> directory which can be used.
+  </para>
+
+  <para>
+   Here is an example of a web frontend build process using <command>gulp</command>. You might use <command>grunt</command>, or anything else.
+  </para>
+
+  <example xml:id="ex-bowerGulpFile">
+   <title>Example build script (<filename>gulpfile.js</filename>)</title>
+<programlisting language="javascript">
+<![CDATA[var gulp = require('gulp');
+
+gulp.task('default', [], function () {
+  gulp.start('build');
+});
+
+gulp.task('build', [], function () {
+  console.log("Just a dummy gulp build");
+  gulp
+    .src(["./bower_components/**/*"])
+    .pipe(gulp.dest("./gulpdist/"));
+});]]>
+</programlisting>
+  </example>
+
+  <example xml:id="ex-buildBowerComponentsDefaultNix">
+   <title>Full example — <filename>default.nix</filename></title>
+<programlisting language="nix">
+{ myWebApp ? { outPath = ./.; name = "myWebApp"; }
+, pkgs ? import &lt;nixpkgs&gt; {}
+}:
+
+pkgs.stdenv.mkDerivation {
+  name = "my-web-app-frontend";
+  src = myWebApp;
+
+  buildInputs = [ pkgs.nodePackages.gulp ];
+
+  bowerComponents = pkgs.buildBowerComponents { <co xml:id="ex-buildBowerComponentsDefault-1" />
+    name = "my-web-app";
+    generated = ./bower-packages.nix;
+    src = myWebApp;
+  };
+
+  buildPhase = ''
+    cp --reflink=auto --no-preserve=mode -R $bowerComponents/bower_components . <co xml:id="ex-buildBowerComponentsDefault-2" />
+    export HOME=$PWD <co xml:id="ex-buildBowerComponentsDefault-3" />
+    ${pkgs.nodePackages.gulp}/bin/gulp build <co xml:id="ex-buildBowerComponentsDefault-4" />
+  '';
+
+  installPhase = "mv gulpdist $out";
+}
+</programlisting>
+  </example>
+
+  <para>
+   A few notes about <xref linkend="ex-buildBowerComponentsDefaultNix" />:
+   <calloutlist>
+    <callout arearefs="ex-buildBowerComponentsDefault-1">
+     <para>
+      The result of <varname>buildBowerComponents</varname> is an input to the frontend build.
+     </para>
+    </callout>
+    <callout arearefs="ex-buildBowerComponentsDefault-2">
+     <para>
+      Whether to symlink or copy the <filename>bower_components</filename> directory depends on the build tool in use. In this case a copy is used to avoid <command>gulp</command> silliness with permissions.
+     </para>
+    </callout>
+    <callout arearefs="ex-buildBowerComponentsDefault-3">
+     <para>
+      <command>gulp</command> requires <varname>HOME</varname> to refer to a writeable directory.
+     </para>
+    </callout>
+    <callout arearefs="ex-buildBowerComponentsDefault-4">
+     <para>
+      The actual build command. Other tools could be used.
+     </para>
+    </callout>
+   </calloutlist>
+  </para>
+ </section>
+
+ <section xml:id="ssec-bower2nix-troubleshooting">
+  <title>Troubleshooting</title>
+
+  <variablelist>
+   <varlistentry>
+    <term>
+     <literal>ENOCACHE</literal> errors from <varname>buildBowerComponents</varname>
+    </term>
+    <listitem>
+     <para>
+      This means that Bower was looking for a package version which doesn't exist in the generated <filename>bower-packages.nix</filename>.
+     </para>
+     <para>
+      If <filename>bower.json</filename> has been updated, then run <command>bower2nix</command> again.
+     </para>
+     <para>
+      It could also be a bug in <command>bower2nix</command> or <command>fetchbower</command>. If possible, try reformulating the version specification in <filename>bower.json</filename>.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+ </section>
+</section>

third_party/nixpkgs/doc/languages-frameworks/coq.xml

@@ -0,0 +1,52 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-coq">
+ <title>Coq</title>
+
+ <para>
+  Coq libraries should be installed in <literal>$(out)/lib/coq/${coq.coq-version}/user-contrib/</literal>. Such directories are automatically added to the <literal>$COQPATH</literal> environment variable by the hook defined in the Coq derivation.
+ </para>
+
+ <para>
+  Some extensions (plugins) might require OCaml and sometimes other OCaml packages. The <literal>coq.ocamlPackages</literal> attribute can be used to depend on the same package set Coq was built against.
+ </para>
+
+ <para>
+  Coq libraries may be compatible with some specific versions of Coq only. The <literal>compatibleCoqVersions</literal> attribute is used to precisely select those versions of Coq that are compatible with this derivation.
+ </para>
+
+ <para>
+  Here is a simple package example. It is a pure Coq library, thus it depends on Coq. It builds on the Mathematical Components library, thus it also takes <literal>mathcomp</literal> as <literal>buildInputs</literal>. Its <literal>Makefile</literal> has been generated using <literal>coq_makefile</literal> so we only have to set the <literal>$COQLIB</literal> variable at install time.
+ </para>
+
+<programlisting>
+{ stdenv, fetchFromGitHub, coq, mathcomp }:
+
+stdenv.mkDerivation rec {
+  name = "coq${coq.coq-version}-multinomials-${version}";
+  version = "1.0";
+  src = fetchFromGitHub {
+    owner = "math-comp";
+    repo = "multinomials";
+    rev = version;
+    sha256 = "1qmbxp1h81cy3imh627pznmng0kvv37k4hrwi2faa101s6bcx55m";
+  };
+
+  buildInputs = [ coq ];
+  propagatedBuildInputs = [ mathcomp ];
+
+  installFlags = "COQLIB=$(out)/lib/coq/${coq.coq-version}/";
+
+  meta = {
+    description = "A Coq/SSReflect Library for Monoidal Rings and Multinomials";
+    inherit (src.meta) homepage;
+    license = stdenv.lib.licenses.cecill-b;
+    inherit (coq.meta) platforms;
+  };
+
+  passthru = {
+    compatibleCoqVersions = v: builtins.elem v [ "8.5" "8.6" "8.7" ];
+  };
+}
+</programlisting>
+</section>

third_party/nixpkgs/doc/languages-frameworks/crystal.section.md

@@ -0,0 +1,71 @@
+# Crystal
+
+## Building a Crystal package
+
+This section uses [Mint](https://github.com/mint-lang/mint) as an example for how to build a Crystal package.
+
+If the Crystal project has any dependencies, the first step is to get a `shards.nix` file encoding those. Get a copy of the project and go to its root directory such that its `shard.lock` file is in the current directory, then run `crystal2nix` in it
+```bash
+$ git clone https://github.com/mint-lang/mint
+$ cd mint
+$ git checkout 0.5.0
+$ nix-shell -p crystal2nix --run crystal2nix
+```
+
+This should have generated a `shards.nix` file.
+
+Next create a Nix file for your derivation and use `pkgs.crystal.buildCrystalPackage` as follows:
+```nix
+with import <nixpkgs> {};
+crystal.buildCrystalPackage rec {
+  pname = "mint";
+  version = "0.5.0";
+
+  src = fetchFromGitHub {
+    owner = "mint-lang";
+    repo = "mint";
+    rev = version;
+    sha256 = "0vxbx38c390rd2ysvbwgh89v2232sh5rbsp3nk9wzb70jybpslvl";
+  };
+
+  # Insert the path to your shards.nix file here
+  shardsFile = ./shards.nix;
+
+  ...
+}
+```
+
+This won't build anything yet, because we haven't told it what files build. We can specify a mapping from binary names to source files with the `crystalBinaries` attribute. The project's compilation instructions should show this. For Mint, the binary is called "mint", which is compiled from the source file `src/mint.cr`, so we'll specify this as follows:
+
+```nix
+  crystalBinaries.mint.src = "src/mint.cr";
+
+  # ...
+```
+
+Additionally you can override the default `crystal build` options (which are currently `--release --progress --no-debug --verbose`) with
+
+```nix
+  crystalBinaries.mint.options = [ "--release" "--verbose" ];
+```
+
+Depending on the project, you might need additional steps to get it to compile successfully. In Mint's case, we need to link against openssl, so in the end the Nix file looks as follows:
+
+```nix
+with import <nixpkgs> {};
+crystal.buildCrystalPackage rec {
+  version = "0.5.0";
+  pname = "mint";
+  src = fetchFromGitHub {
+    owner = "mint-lang";
+    repo = "mint";
+    rev = version;
+    sha256 = "0vxbx38c390rd2ysvbwgh89v2232sh5rbsp3nk9wzb70jybpslvl";
+  };
+
+  shardsFile = ./shards.nix;
+  crystalBinaries.mint.src = "src/mint.cr";
+
+  buildInputs = [ openssl ];
+}
+```

third_party/nixpkgs/doc/languages-frameworks/dotnet.section.md

@@ -0,0 +1,75 @@
+# Dotnet
+
+## Local Development Workflow
+
+For local development, it's recommended to use nix-shell to create a dotnet environment:
+
+```
+# shell.nix
+with import <nixpkgs> {};
+
+mkShell {
+  name = "dotnet-env";
+  buildInputs = [
+    dotnet-sdk_3
+  ];
+}
+```
+
+### Using many sdks in a workflow
+
+It's very likely that more than one sdk will be needed on a given project. Dotnet provides several different frameworks (E.g dotnetcore, aspnetcore, etc.) as well as many versions for a given framework. Normally, dotnet is able to fetch a framework and install it relative to the executable. However, this would mean writing to the nix store in nixpkgs, which is read-only. To support the many-sdk use case, one can compose an environment using `dotnetCorePackages.combinePackages`:
+
+```
+with import <nixpkgs> {};
+
+mkShell {
+  name = "dotnet-env";
+  buildInputs = [
+    (with dotnetCorePackages; combinePackages [
+      sdk_3_1
+      sdk_3_0
+      sdk_2_1
+    ])
+  ];
+}
+```
+
+This will produce a dotnet installation that has the dotnet 3.1, 3.0, and 2.1 sdk. The first sdk listed will have it's cli utility present in the resulting environment. Example info output:
+
+```
+$ dotnet --info
+.NET Core SDK (reflecting any global.json):
+ Version:   3.1.101
+ Commit:    b377529961
+
+...
+
+.NET Core SDKs installed:
+  2.1.803 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/sdk]
+  3.0.102 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/sdk]
+  3.1.101 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/sdk]
+
+.NET Core runtimes installed:
+  Microsoft.AspNetCore.All 2.1.15 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.AspNetCore.All]
+  Microsoft.AspNetCore.App 2.1.15 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.AspNetCore.App]
+  Microsoft.AspNetCore.App 3.0.2 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.AspNetCore.App]
+  Microsoft.AspNetCore.App 3.1.1 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.AspNetCore.App]
+  Microsoft.NETCore.App 2.1.15 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.NETCore.App]
+  Microsoft.NETCore.App 3.0.2 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.NETCore.App]
+  Microsoft.NETCore.App 3.1.1 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.NETCore.App]
+```
+
+## dotnet-sdk vs dotnetCorePackages.sdk
+
+The `dotnetCorePackages.sdk_X_Y` is preferred over the old dotnet-sdk as both major and minor version are very important for a dotnet environment. If a given minor version isn't present (or was changed), then this will likely break your ability to build a project.
+
+## dotnetCorePackages.sdk vs dotnetCorePackages.netcore vs dotnetCorePackages.aspnetcore
+
+The `dotnetCorePackages.sdk` contains both a runtime and the full sdk of a given version. The `netcore` and `aspnetcore` packages are meant to serve as minimal runtimes to deploy alongside already built applications.
+
+## Packaging a Dotnet Application
+
+Ideally, we would like to build against the sdk, then only have the dotnet runtime available in the runtime closure.
+
+TODO: Create closure-friendly way to package dotnet applications

third_party/nixpkgs/doc/languages-frameworks/emscripten.section.md

@@ -0,0 +1,185 @@
+# Emscripten
+
+[Emscripten](https://github.com/kripken/emscripten): An LLVM-to-JavaScript Compiler
+
+This section of the manual covers how to use `emscripten` in nixpkgs.
+
+Minimal requirements:
+
+* nix
+* nixpkgs
+
+Modes of use of `emscripten`:
+
+* **Imperative usage** (on the command line):
+
+   If you want to work with `emcc`, `emconfigure` and `emmake` as you are used to from Ubuntu and similar distributions you can use these commands:
+
+    * `nix-env -i emscripten`
+    * `nix-shell -p emscripten`
+
+* **Declarative usage**:
+
+    This mode is far more power full since this makes use of `nix` for dependency management of emscripten libraries and targets by using the `mkDerivation` which is implemented by `pkgs.emscriptenStdenv` and `pkgs.buildEmscriptenPackage`. The source for the packages is in `pkgs/top-level/emscripten-packages.nix` and the abstraction behind it in `pkgs/development/em-modules/generic/default.nix`.
+    * build and install all packages: 
+        * `nix-env -iA emscriptenPackages` 
+          
+    * dev-shell for zlib implementation hacking: 
+        * `nix-shell -A emscriptenPackages.zlib` 
+
+
+## Imperative usage
+
+A few things to note:
+
+* `export EMCC_DEBUG=2` is nice for debugging
+* `~/.emscripten`, the build artifact cache sometimes creates issues and needs to be removed from time to time
+
+
+## Declarative usage
+
+Let's see two different examples from `pkgs/top-level/emscripten-packages.nix`:
+
+* `pkgs.zlib.override`
+* `pkgs.buildEmscriptenPackage`
+
+Both are interesting concepts.
+
+A special requirement of the `pkgs.buildEmscriptenPackage` is the `doCheck = true` is a default meaning that each emscriptenPackage requires a `checkPhase` implemented.
+
+* Use `export EMCC_DEBUG=2` from within a emscriptenPackage's `phase` to get more detailed debug output what is going wrong.
+* ~/.emscripten cache is requiring us to set `HOME=$TMPDIR` in individual phases. This makes compilation slower but also makes it more deterministic.
+
+### Usage 1: pkgs.zlib.override
+
+This example uses `zlib` from nixpkgs but instead of compiling **C** to **ELF** it compiles **C** to **JS** since we were using `pkgs.zlib.override` and changed stdenv to `pkgs.emscriptenStdenv`. A few adaptions and hacks were set in place to make it working. One advantage is that when `pkgs.zlib` is updated, it will automatically update this package as well. However, this can also be the downside...
+
+See the `zlib` example:
+
+    zlib = (pkgs.zlib.override {
+      stdenv = pkgs.emscriptenStdenv;
+    }).overrideDerivation
+    (old: rec {
+      buildInputs = old.buildInputs ++ [ pkgconfig ];
+      # we need to reset this setting!
+      NIX_CFLAGS_COMPILE="";
+      configurePhase = ''
+        # FIXME: Some tests require writing at $HOME
+        HOME=$TMPDIR
+        runHook preConfigure
+
+        #export EMCC_DEBUG=2
+        emconfigure ./configure --prefix=$out --shared
+
+        runHook postConfigure
+      '';
+      dontStrip = true;
+      outputs = [ "out" ];
+      buildPhase = ''
+        emmake make
+      '';
+      installPhase = ''
+        emmake make install
+      '';
+      checkPhase = ''
+        echo "================= testing zlib using node ================="
+
+        echo "Compiling a custom test"
+        set -x
+        emcc -O2 -s EMULATE_FUNCTION_POINTER_CASTS=1 test/example.c -DZ_SOLO \
+        libz.so.${old.version} -I . -o example.js
+
+        echo "Using node to execute the test"
+        ${pkgs.nodejs}/bin/node ./example.js 
+
+        set +x
+        if [ $? -ne 0 ]; then
+          echo "test failed for some reason"
+          exit 1;
+        else
+          echo "it seems to work! very good."
+        fi
+        echo "================= /testing zlib using node ================="
+      '';
+
+      postPatch = pkgs.stdenv.lib.optionalString pkgs.stdenv.isDarwin ''
+        substituteInPlace configure \
+          --replace '/usr/bin/libtool' 'ar' \
+          --replace 'AR="libtool"' 'AR="ar"' \
+          --replace 'ARFLAGS="-o"' 'ARFLAGS="-r"'
+      '';
+    });
+
+### Usage 2: pkgs.buildEmscriptenPackage
+
+This `xmlmirror` example features a emscriptenPackage which is defined completely from this context and no `pkgs.zlib.override` is used. 
+
+    xmlmirror = pkgs.buildEmscriptenPackage rec {
+      name = "xmlmirror";
+
+      buildInputs = [ pkgconfig autoconf automake libtool gnumake libxml2 nodejs openjdk json_c ];
+      nativeBuildInputs = [ pkgconfig zlib ];
+
+      src = pkgs.fetchgit {
+        url = "https://gitlab.com/odfplugfest/xmlmirror.git";
+        rev = "4fd7e86f7c9526b8f4c1733e5c8b45175860a8fd";
+        sha256 = "1jasdqnbdnb83wbcnyrp32f36w3xwhwp0wq8lwwmhqagxrij1r4b";
+      };
+
+      configurePhase = ''
+        rm -f fastXmlLint.js*
+        # a fix for ERROR:root:For asm.js, TOTAL_MEMORY must be a multiple of 16MB, was 234217728
+        # https://gitlab.com/odfplugfest/xmlmirror/issues/8
+        sed -e "s/TOTAL_MEMORY=234217728/TOTAL_MEMORY=268435456/g" -i Makefile.emEnv
+        # https://github.com/kripken/emscripten/issues/6344
+        # https://gitlab.com/odfplugfest/xmlmirror/issues/9
+        sed -e "s/\$(JSONC_LDFLAGS) \$(ZLIB_LDFLAGS) \$(LIBXML20_LDFLAGS)/\$(JSONC_LDFLAGS) \$(LIBXML20_LDFLAGS) \$(ZLIB_LDFLAGS) /g" -i Makefile.emEnv
+        # https://gitlab.com/odfplugfest/xmlmirror/issues/11
+        sed -e "s/-o fastXmlLint.js/-s EXTRA_EXPORTED_RUNTIME_METHODS='[\"ccall\", \"cwrap\"]' -o fastXmlLint.js/g" -i Makefile.emEnv
+      '';
+
+      buildPhase = ''
+        HOME=$TMPDIR
+        make -f Makefile.emEnv
+      '';
+
+      outputs = [ "out" "doc" ];
+
+      installPhase = ''
+        mkdir -p $out/share
+        mkdir -p $doc/share/${name}
+
+        cp Demo* $out/share
+        cp -R codemirror-5.12 $out/share
+        cp fastXmlLint.js* $out/share
+        cp *.xsd $out/share
+        cp *.js $out/share
+        cp *.xhtml $out/share
+        cp *.html $out/share
+        cp *.json $out/share
+        cp *.rng $out/share
+        cp README.md $doc/share/${name}
+      '';
+      checkPhase = ''
+
+      '';
+    }; 
+
+### Declarative debugging
+
+Use `nix-shell -I nixpkgs=/some/dir/nixpkgs -A emscriptenPackages.libz` and from there you can go trough the individual steps. This makes it easy to build a good `unit test` or list the files of the project.
+
+1. `nix-shell -I nixpkgs=/some/dir/nixpkgs -A emscriptenPackages.libz`
+2. `cd /tmp/`
+3. `unpackPhase`
+4. cd libz-1.2.3
+5. `configurePhase`
+6. `buildPhase`
+7. ... happy hacking...
+
+## Summary
+
+Using this toolchain makes it easy to leverage `nix` from NixOS, MacOSX or even Windows (WSL+ubuntu+nix). This toolchain is reproducible, behaves like the rest of the packages from nixpkgs and contains a set of well working examples to learn and adapt from.
+
+If in trouble, ask the maintainers.
+

third_party/nixpkgs/doc/languages-frameworks/gnome.xml

@@ -0,0 +1,282 @@
+<section xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-language-gnome">
+ <title>GNOME</title>
+
+ <section xml:id="ssec-gnome-packaging">
+  <title>Packaging GNOME applications</title>
+
+  <para>
+   Programs in the GNOME universe are written in various languages but they all use GObject-based libraries like GLib, GTK or GStreamer. These libraries are often modular, relying on looking into certain directories to find their modules. However, due to Nix’s specific file system organization, this will fail without our intervention. Fortunately, the libraries usually allow overriding the directories through environment variables, either natively or thanks to a patch in nixpkgs. <link xlink:href="#fun-wrapProgram">Wrapping</link> the executables to ensure correct paths are available to the application constitutes a significant part of packaging a modern desktop application. In this section, we will describe various modules needed by such applications, environment variables needed to make the modules load, and finally a script that will do the work for us.
+  </para>
+
+  <section xml:id="ssec-gnome-settings">
+   <title>Settings</title>
+
+   <para>
+    <link xlink:href="https://developer.gnome.org/gio/stable/GSettings.html">GSettings</link> API is often used for storing settings. GSettings schemas are required, to know the type and other metadata of the stored values. GLib looks for <filename>glib-2.0/schemas/gschemas.compiled</filename> files inside the directories of <envar>XDG_DATA_DIRS</envar>.
+   </para>
+
+   <para>
+    On Linux, GSettings API is implemented using <link xlink:href="https://wiki.gnome.org/Projects/dconf">dconf</link> backend. You will need to add <literal>dconf</literal> GIO module to <envar>GIO_EXTRA_MODULES</envar> variable, otherwise the <literal>memory</literal> backend will be used and the saved settings will not be persistent.
+   </para>
+
+   <para>
+    Last you will need the dconf database D-Bus service itself. You can enable it using <option>programs.dconf.enable</option>.
+   </para>
+
+   <para>
+    Some applications will also require <package>gsettings-desktop-schemas</package> for things like reading proxy configuration or user interface customization. This dependency is often not mentioned by upstream, you should grep for <literal>org.gnome.desktop</literal> and <literal>org.gnome.system</literal> to see if the schemas are needed.
+   </para>
+  </section>
+
+  <section xml:id="ssec-gnome-icons">
+   <title>Icons</title>
+
+   <para>
+    When an application uses icons, an icon theme should be available in <envar>XDG_DATA_DIRS</envar> during runtime. The package for the default, icon-less <link xlink:href="https://www.freedesktop.org/wiki/Software/icon-theme/">hicolor-icon-theme</link> (should be propagated by every icon theme) contains <link linkend="ssec-gnome-hooks-hicolor-icon-theme">a setup hook</link> that will pick up icon themes from <literal>buildInputs</literal> and pass it to our wrapper. Unfortunately, relying on that would mean every user has to download the theme included in the package expression no matter their preference. For that reason, we leave the installation of icon theme on the user. If you use one of the desktop environments, you probably already have an icon theme installed.
+   </para>
+
+   <para>
+    To avoid costly file system access when locating icons, GTK, <link xlink:href="https://woboq.com/blog/qicon-reads-gtk-icon-cache-in-qt57.html">as well as Qt</link>, can rely on <filename>icon-theme.cache</filename> files from the themes’ top-level directories. These files are generated using <command>gtk-update-icon-cache</command>, which is expected to be run whenever an icon is added or removed to an icon theme (typically an application icon into <literal>hicolor</literal> theme) and some programs do indeed run this after icon installation. However, since packages are installed into their own prefix by Nix, this would lead to conflicts. For that reason, <package>gtk3</package> provides a <link xlink:href="#ssec-gnome-hooks-gtk-drop-icon-theme-cache">setup hook</link> that will clean the file from installation. Since most applications only ship their own icon that will be loaded on start-up, it should not affect them too much. On the other hand, icon themes are much larger and more widely used so we need to cache them. Because we recommend installing icon themes globally, we will generate the cache files from all packages in a profile using a NixOS module. You can enable the cache generation using <option>gtk.iconCache.enable</option> option if your desktop environment does not already do that.
+   </para>
+  </section>
+
+  <section xml:id="ssec-gnome-themes">
+   <title>GTK Themes</title>
+
+   <para>
+    Previously, a GTK theme needed to be in <envar>XDG_DATA_DIRS</envar>. This is no longer necessary for most programs since GTK incorporated Adwaita theme. Some programs (for example, those designed for <link xlink:href="https://elementary.io/docs/human-interface-guidelines#human-interface-guidelines">elementary HIG</link>) might require a special theme like <package>pantheon.elementary-gtk-theme</package>.
+   </para>
+  </section>
+
+  <section xml:id="ssec-gnome-typelibs">
+   <title>GObject introspection typelibs</title>
+
+   <para>
+    <link xlink:href="https://wiki.gnome.org/Projects/GObjectIntrospection">GObject introspection</link> allows applications to use C libraries in other languages easily. It does this through <literal>typelib</literal> files searched in <envar>GI_TYPELIB_PATH</envar>.
+   </para>
+  </section>
+
+  <section xml:id="ssec-gnome-plugins">
+   <title>Various plug-ins</title>
+
+   <para>
+    If your application uses <link xlink:href="https://gstreamer.freedesktop.org/">GStreamer</link> or <link xlink:href="https://wiki.gnome.org/Projects/Grilo">Grilo</link>, you should set <envar>GST_PLUGIN_SYSTEM_PATH_1_0</envar> and <envar>GRL_PLUGIN_PATH</envar>, respectively.
+   </para>
+  </section>
+ </section>
+
+ <section xml:id="ssec-gnome-hooks">
+  <title>Onto <package>wrapGAppsHook</package></title>
+
+  <para>
+   Given the requirements above, the package expression would become messy quickly:
+<programlisting>
+preFixup = ''
+  for f in $(find $out/bin/ $out/libexec/ -type f -executable); do
+    wrapProgram "$f" \
+      --prefix GIO_EXTRA_MODULES : "${getLib dconf}/lib/gio/modules" \
+      --prefix XDG_DATA_DIRS : "$out/share" \
+      --prefix XDG_DATA_DIRS : "$out/share/gsettings-schemas/${name}" \
+      --prefix XDG_DATA_DIRS : "${gsettings-desktop-schemas}/share/gsettings-schemas/${gsettings-desktop-schemas.name}" \
+      --prefix XDG_DATA_DIRS : "${hicolor-icon-theme}/share" \
+      --prefix GI_TYPELIB_PATH : "${lib.makeSearchPath "lib/girepository-1.0" [ pango json-glib ]}"
+  done
+'';
+</programlisting>
+   Fortunately, there is <package>wrapGAppsHook</package>, that does the wrapping for us. In particular, it works in conjunction with other setup hooks that will populate the variable:
+   <itemizedlist>
+    <listitem xml:id="ssec-gnome-hooks-wrapgappshook">
+     <para>
+      <package>wrapGAppsHook</package> itself will add the package’s <filename>share</filename> directory to <envar>XDG_DATA_DIRS</envar>.
+     </para>
+    </listitem>
+    <listitem xml:id="ssec-gnome-hooks-glib">
+     <para>
+      <package>glib</package> setup hook will populate <envar>GSETTINGS_SCHEMAS_PATH</envar> and then <package>wrapGAppsHook</package> will prepend it to <envar>XDG_DATA_DIRS</envar>.
+     </para>
+    </listitem>
+    <listitem xml:id="ssec-gnome-hooks-gtk-drop-icon-theme-cache">
+     <para>
+      One of <package>gtk3</package>’s setup hooks will remove <filename>icon-theme.cache</filename> files from package’s icon theme directories to avoid conflicts. Icon theme packages should prevent this with <code>dontDropIconThemeCache = true;</code>.
+     </para>
+    </listitem>
+    <listitem xml:id="ssec-gnome-hooks-dconf">
+     <para>
+      <package>dconf.lib</package> is a dependency of <package>wrapGAppsHook</package>, which then also adds it to the <envar>GIO_EXTRA_MODULES</envar> variable.
+     </para>
+    </listitem>
+    <listitem xml:id="ssec-gnome-hooks-hicolor-icon-theme">
+     <para>
+      <package>hicolor-icon-theme</package>’s setup hook will add icon themes to <envar>XDG_ICON_DIRS</envar> which is prepended to <envar>XDG_DATA_DIRS</envar> by <package>wrapGAppsHook</package>.
+     </para>
+    </listitem>
+    <listitem xml:id="ssec-gnome-hooks-gobject-introspection">
+     <para>
+      <package>gobject-introspection</package> setup hook populates <envar>GI_TYPELIB_PATH</envar> variable with <filename>lib/girepository-1.0</filename> directories of dependencies, which is then added to wrapper by <package>wrapGAppsHook</package>. It also adds <filename>share</filename> directories of dependencies to <envar>XDG_DATA_DIRS</envar>, which is intended to promote GIR files but it also <link xlink:href="https://github.com/NixOS/nixpkgs/issues/32790">pollutes the closures</link> of packages using <package>wrapGAppsHook</package>.
+     </para>
+     <warning>
+      <para>
+       The setup hook <link xlink:href="https://github.com/NixOS/nixpkgs/issues/56943">currently</link> does not work in expressions with <literal>strictDeps</literal> enabled, like Python packages. In those cases, you will need to disable it with <code>strictDeps = false;</code>.
+      </para>
+     </warning>
+    </listitem>
+    <listitem xml:id="ssec-gnome-hooks-gst-grl-plugins">
+     <para>
+      Setup hooks of <package>gst_all_1.gstreamer</package> and <package>gnome3.grilo</package> will populate the <envar>GST_PLUGIN_SYSTEM_PATH_1_0</envar> and <envar>GRL_PLUGIN_PATH</envar> variables, respectively, which will then be added to the wrapper by <literal>wrapGAppsHook</literal>.
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+
+  <para>
+   You can also pass additional arguments to <literal>makeWrapper</literal> using <literal>gappsWrapperArgs</literal> in <literal>preFixup</literal> hook:
+<programlisting>
+preFixup = ''
+  gappsWrapperArgs+=(
+    # Thumbnailers
+    --prefix XDG_DATA_DIRS : "${gdk-pixbuf}/share"
+    --prefix XDG_DATA_DIRS : "${librsvg}/share"
+    --prefix XDG_DATA_DIRS : "${shared-mime-info}/share"
+  )
+'';
+</programlisting>
+  </para>
+ </section>
+
+ <section xml:id="ssec-gnome-updating">
+  <title>Updating GNOME packages</title>
+
+  <para>
+   Most GNOME package offer <link linkend="var-passthru-updateScript"><literal>updateScript</literal></link>, it is therefore possible to update to latest source tarball by running <command>nix-shell maintainers/scripts/update.nix --argstr package gnome3.nautilus</command> or even en masse with <command>nix-shell maintainers/scripts/update.nix --argstr path gnome3</command>. Read the package’s <filename>NEWS</filename> file to see what changed.
+  </para>
+ </section>
+
+ <section xml:id="ssec-gnome-common-issues">
+  <title>Frequently encountered issues</title>
+
+  <variablelist>
+   <varlistentry xml:id="ssec-gnome-common-issues-no-schemas">
+    <term>
+     <computeroutput>GLib-GIO-ERROR **: <replaceable>06:04:50.903</replaceable>: No GSettings schemas are installed on the system</computeroutput>
+    </term>
+    <listitem>
+     <para>
+      There are no schemas avalable in <envar>XDG_DATA_DIRS</envar>. Temporarily add a random package containing schemas like <package>gsettings-desktop-schemas</package> to <literal>buildInputs</literal>. <link linkend="ssec-gnome-hooks-glib"><package>glib</package></link> and <link linkend="ssec-gnome-hooks-wrapgappshook"><package>wrapGAppsHook</package></link> setup hooks will take care of making the schemas available to application and you will see the actual missing schemas with the <link linkend="ssec-gnome-common-issues-missing-schema">next error</link>. Or you can try looking through the source code for the actual schemas used.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="ssec-gnome-common-issues-missing-schema">
+    <term>
+     <computeroutput>GLib-GIO-ERROR **: <replaceable>06:04:50.903</replaceable>: Settings schema ‘<replaceable>org.gnome.foo</replaceable>’ is not installed</computeroutput>
+    </term>
+    <listitem>
+     <para>
+      Package is missing some GSettings schemas. You can find out the package containing the schema with <command>nix-locate <replaceable>org.gnome.foo</replaceable>.gschema.xml</command> and let the hooks handle the wrapping as <link linkend="ssec-gnome-common-issues-no-schemas">above</link>.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="ssec-gnome-common-issues-double-wrapped">
+    <term>
+     When using <package>wrapGAppsHook</package> with special derivers you can end up with double wrapped binaries.
+    </term>
+    <listitem>
+     <para>
+      This is because derivers like <function>python.pkgs.buildPythonApplication</function> or <function>qt5.mkDerivation</function> have setup-hooks automatically added that produce wrappers with <package>makeWrapper</package>. The simplest way to workaround that is to disable the <package>wrapGAppsHook</package> automatic wrapping with <code>dontWrapGApps = true;</code> and pass the arguments it intended to pass to <package>makeWrapper</package> to another.
+     </para>
+     <para>
+      In the case of a Python application it could look like:
+<programlisting>
+python3.pkgs.buildPythonApplication {
+  pname = "gnome-music";
+  version = "3.32.2";
+
+  nativeBuildInputs = [
+    wrapGAppsHook
+    gobject-introspection
+    ...
+  ];
+
+  dontWrapGApps = true;
+
+  # Arguments to be passed to `makeWrapper`, only used by buildPython*
+  preFixup = ''
+    makeWrapperArgs+=("''${gappsWrapperArgs[@]}")
+  '';
+}
+</programlisting>
+      And for a QT app like:
+<programlisting>
+mkDerivation {
+  pname = "calibre";
+  version = "3.47.0";
+
+  nativeBuildInputs = [
+    wrapGAppsHook
+    qmake
+    ...
+  ];
+
+  dontWrapGApps = true;
+
+  # Arguments to be passed to `makeWrapper`, only used by qt5’s mkDerivation
+  preFixup = ''
+    qtWrapperArgs+=("''${gappsWrapperArgs[@]}")
+  '';
+}
+</programlisting>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="ssec-gnome-common-issues-unwrappable-package">
+    <term>
+     I am packaging a project that cannot be wrapped, like a library or GNOME Shell extension.
+    </term>
+    <listitem>
+     <para>
+      You can rely on applications depending on the library setting the necessary environment variables but that is often easy to miss. Instead we recommend to patch the paths in the source code whenever possible. Here are some examples:
+      <itemizedlist>
+       <listitem xml:id="ssec-gnome-common-issues-unwrappable-package-gnome-shell-ext">
+        <para>
+         <link xlink:href="https://github.com/NixOS/nixpkgs/blob/7bb8f05f12ca3cff9da72b56caa2f7472d5732bc/pkgs/desktops/gnome-3/core/gnome-shell-extensions/default.nix#L21-L24">Replacing a <envar>GI_TYPELIB_PATH</envar> in GNOME Shell extension</link> – we are using <function>substituteAll</function> to include the path to a typelib into a patch.
+        </para>
+       </listitem>
+       <listitem xml:id="ssec-gnome-common-issues-unwrappable-package-gsettings">
+        <para>
+         The following examples are hardcoding GSettings schema paths. To get the schema paths we use the functions
+         <itemizedlist>
+          <listitem>
+           <para>
+            <function>glib.getSchemaPath</function> Takes a nix package attribute as an argument.
+           </para>
+          </listitem>
+          <listitem>
+           <para>
+            <function>glib.makeSchemaPath</function> Takes a package output like <literal>$out</literal> and a derivation name. You should use this if the schemas you need to hardcode are in the same derivation.
+           </para>
+          </listitem>
+         </itemizedlist>
+        </para>
+        <para xml:id="ssec-gnome-common-issues-unwrappable-package-gsettings-vala">
+         <link xlink:href="https://github.com/NixOS/nixpkgs/blob/7bb8f05f12ca3cff9da72b56caa2f7472d5732bc/pkgs/desktops/pantheon/apps/elementary-files/default.nix#L78-L86">Hard-coding GSettings schema path in Vala plug-in (dynamically loaded library)</link> – here, <function>substituteAll</function> cannot be used since the schema comes from the same package preventing us from pass its path to the function, probably due to a <link xlink:href="https://github.com/NixOS/nix/issues/1846">Nix bug</link>.
+        </para>
+        <para xml:id="ssec-gnome-common-issues-unwrappable-package-gsettings-c">
+         <link xlink:href="https://github.com/NixOS/nixpkgs/blob/29c120c065d03b000224872251bed93932d42412/pkgs/development/libraries/glib-networking/default.nix#L31-L34">Hard-coding GSettings schema path in C library</link> – nothing special other than using <link xlink:href="https://github.com/NixOS/nixpkgs/pull/67957#issuecomment-527717467">Coccinelle patch</link> to generate the patch itself.
+        </para>
+       </listitem>
+      </itemizedlist>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="ssec-gnome-common-issues-weird-location">
+    <term>
+     I need to wrap a binary outside <filename>bin</filename> and <filename>libexec</filename> directories.
+    </term>
+    <listitem>
+     <para>
+      You can manually trigger the wrapping with <function>wrapGApp</function> in <literal>preFixup</literal> phase. It takes a path to a program as a first argument; the remaining arguments are passed directly to <function xlink:href="#fun-wrapProgram">wrapProgram</function> function.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+ </section>
+</section>

third_party/nixpkgs/doc/languages-frameworks/go.xml

@@ -0,0 +1,215 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-go">
+ <title>Go</title>
+
+ <section xml:id="ssec-go-modules">
+  <title>Go modules</title>
+
+  <para>
+   The function <varname> buildGoModule </varname> builds Go programs managed with Go modules. It builds a <link xlink:href="https://github.com/golang/go/wiki/Modules">Go modules</link> through a two phase build:
+   <itemizedlist>
+    <listitem>
+     <para>
+      An intermediate fetcher derivation. This derivation will be used to fetch all of the dependencies of the Go module.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      A final derivation will use the output of the intermediate derivation to build the binaries and produce the final output.
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+
+  <example xml:id='ex-buildGoModule'>
+   <title>buildGoModule</title>
+<programlisting>
+pet = buildGoModule rec {
+  pname = "pet";
+  version = "0.3.4";
+
+  src = fetchFromGitHub {
+    owner = "knqyf263";
+    repo = "pet";
+    rev = "v${version}";
+    sha256 = "0m2fzpqxk7hrbxsgqplkg7h2p7gv6s1miymv3gvw0cz039skag0s";
+  };
+
+  modSha256 = "1879j77k96684wi554rkjxydrj8g3hpp0kvxz03sd8dmwr3lh83j"; <co xml:id='ex-buildGoModule-1' />
+
+  subPackages = [ "." ]; <co xml:id='ex-buildGoModule-2' />
+
+  meta = with lib; {
+    description = "Simple command-line snippet manager, written in Go";
+    homepage = "https://github.com/knqyf263/pet";
+    license = licenses.mit;
+    maintainers = with maintainers; [ kalbasit ];
+    platforms = platforms.linux ++ platforms.darwin;
+  };
+}
+</programlisting>
+  </example>
+
+  <para>
+   <xref linkend='ex-buildGoModule'/> is an example expression using buildGoModule, the following arguments are of special significance to the function:
+   <calloutlist>
+    <callout arearefs='ex-buildGoModule-1'>
+     <para>
+      <varname>modSha256</varname> is the hash of the output of the intermediate fetcher derivation.
+     </para>
+    </callout>
+    <callout arearefs='ex-buildGoModule-2'>
+     <para>
+      <varname>subPackages</varname> limits the builder from building child packages that have not been listed. If <varname>subPackages</varname> is not specified, all child packages will be built.
+     </para>
+    </callout>
+   </calloutlist>
+  </para>
+
+  <para>
+    <varname>modSha256</varname> can also take <varname>null</varname> as an input.
+
+    When `null` is used as a value, the derivation won't be a
+    fixed-output derivation but disable the build sandbox instead. This can be useful outside
+    of nixpkgs where re-generating the modSha256 on each mod.sum changes is cumbersome,
+    but will fail to build by Hydra, as builds with a disabled sandbox are discouraged.
+  </para>
+ </section>
+
+ <section xml:id="ssec-go-legacy">
+  <title>Go legacy</title>
+
+  <para>
+   The function <varname> buildGoPackage </varname> builds legacy Go programs, not supporting Go modules.
+  </para>
+
+  <example xml:id='ex-buildGoPackage'>
+   <title>buildGoPackage</title>
+<programlisting>
+deis = buildGoPackage rec {
+  pname = "deis";
+  version = "1.13.0";
+
+  goPackagePath = "github.com/deis/deis"; <co xml:id='ex-buildGoPackage-1' />
+  subPackages = [ "client" ]; <co xml:id='ex-buildGoPackage-2' />
+
+  src = fetchFromGitHub {
+    owner = "deis";
+    repo = "deis";
+    rev = "v${version}";
+    sha256 = "1qv9lxqx7m18029lj8cw3k7jngvxs4iciwrypdy0gd2nnghc68sw";
+  };
+
+  goDeps = ./deps.nix; <co xml:id='ex-buildGoPackage-3' />
+
+  buildFlags = [ "--tags" "release" ]; <co xml:id='ex-buildGoPackage-4' />
+}
+</programlisting>
+  </example>
+
+  <para>
+   <xref linkend='ex-buildGoPackage'/> is an example expression using buildGoPackage, the following arguments are of special significance to the function:
+   <calloutlist>
+    <callout arearefs='ex-buildGoPackage-1'>
+     <para>
+      <varname>goPackagePath</varname> specifies the package's canonical Go import path.
+     </para>
+    </callout>
+    <callout arearefs='ex-buildGoPackage-2'>
+     <para>
+      <varname>subPackages</varname> limits the builder from building child packages that have not been listed. If <varname>subPackages</varname> is not specified, all child packages will be built.
+     </para>
+     <para>
+      In this example only <literal>github.com/deis/deis/client</literal> will be built.
+     </para>
+    </callout>
+    <callout arearefs='ex-buildGoPackage-3'>
+     <para>
+      <varname>goDeps</varname> is where the Go dependencies of a Go program are listed as a list of package source identified by Go import path. It could be imported as a separate <varname>deps.nix</varname> file for readability. The dependency data structure is described below.
+     </para>
+    </callout>
+    <callout arearefs='ex-buildGoPackage-4'>
+     <para>
+      <varname>buildFlags</varname> is a list of flags passed to the go build command.
+     </para>
+    </callout>
+   </calloutlist>
+  </para>
+
+  <para>
+   The <varname>goDeps</varname> attribute can be imported from a separate <varname>nix</varname> file that defines which Go libraries are needed and should be included in <varname>GOPATH</varname> for <varname>buildPhase</varname>.
+  </para>
+
+  <example xml:id='ex-goDeps'>
+   <title>deps.nix</title>
+<programlisting>
+[ <co xml:id='ex-goDeps-1' />
+  {
+    goPackagePath = "gopkg.in/yaml.v2"; <co xml:id='ex-goDeps-2' />
+    fetch = {
+      type = "git"; <co xml:id='ex-goDeps-3' />
+      url = "https://gopkg.in/yaml.v2";
+      rev = "a83829b6f1293c91addabc89d0571c246397bbf4";
+      sha256 = "1m4dsmk90sbi17571h6pld44zxz7jc4lrnl4f27dpd1l8g5xvjhh";
+    };
+  }
+  {
+    goPackagePath = "github.com/docopt/docopt-go";
+    fetch = {
+      type = "git";
+      url = "https://github.com/docopt/docopt-go";
+      rev = "784ddc588536785e7299f7272f39101f7faccc3f";
+      sha256 = "0wwz48jl9fvl1iknvn9dqr4gfy1qs03gxaikrxxp9gry6773v3sj";
+    };
+  }
+]
+</programlisting>
+  </example>
+
+  <para>
+   <calloutlist>
+    <callout arearefs='ex-goDeps-1'>
+     <para>
+      <varname>goDeps</varname> is a list of Go dependencies.
+     </para>
+    </callout>
+    <callout arearefs='ex-goDeps-2'>
+     <para>
+      <varname>goPackagePath</varname> specifies Go package import path.
+     </para>
+    </callout>
+    <callout arearefs='ex-goDeps-3'>
+     <para>
+      <varname>fetch type</varname> that needs to be used to get package source. If <varname>git</varname> is used there should be <varname>url</varname>, <varname>rev</varname> and <varname>sha256</varname> defined next to it.
+     </para>
+    </callout>
+   </calloutlist>
+  </para>
+
+  <para>
+   To extract dependency information from a Go package in automated way use <link xlink:href="https://github.com/kamilchm/go2nix">go2nix</link>. It can produce complete derivation and <varname>goDeps</varname> file for Go programs.
+  </para>
+
+  <para>
+   <varname>buildGoPackage</varname> produces <xref linkend='chap-multiple-output' xrefstyle="select: title" /> where <varname>bin</varname> includes program binaries. You can test build a Go binary as follows:
+<screen>
+<prompt>$ </prompt>nix-build -A deis.bin
+</screen>
+   or build all outputs with:
+<screen>
+<prompt>$ </prompt>nix-build -A deis.all
+</screen>
+   <varname>bin</varname> output will be installed by default with <varname>nix-env -i</varname> or <varname>systemPackages</varname>.
+  </para>
+
+  <para>
+   You may use Go packages installed into the active Nix profiles by adding the following to your ~/.bashrc:
+<screen>
+for p in $NIX_PROFILES; do
+    GOPATH="$p/share/go:$GOPATH"
+done
+</screen>
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/languages-frameworks/idris.section.md

@@ -0,0 +1,144 @@
+# Idris
+
+## Installing Idris
+
+The easiest way to get a working idris version is to install the `idris` attribute:
+
+```
+$ # On NixOS
+$ nix-env -i nixos.idris
+$ # On non-NixOS
+$ nix-env -i nixpkgs.idris
+```
+
+This however only provides the `prelude` and `base` libraries. To install idris with additional libraries, you can use the `idrisPackages.with-packages` function, e.g. in an overlay in `~/.config/nixpkgs/overlays/my-idris.nix`:
+
+```nix
+self: super: {
+  myIdris = with self.idrisPackages; with-packages [ contrib pruviloj ];
+}
+```
+
+And then:
+
+```
+$ # On NixOS
+$ nix-env -iA nixos.myIdris
+$ # On non-NixOS
+$ nix-env -iA nixpkgs.myIdris
+```
+
+To see all available Idris packages:
+```
+$ # On NixOS
+$ nix-env -qaPA nixos.idrisPackages
+$ # On non-NixOS
+$ nix-env -qaPA nixpkgs.idrisPackages
+```
+
+Similarly, entering a `nix-shell`:
+```
+$ nix-shell -p 'idrisPackages.with-packages (with idrisPackages; [ contrib pruviloj ])'
+```
+
+## Starting Idris with library support
+
+To have access to these libraries in idris, call it with an argument `-p <library name>` for each library:
+
+```
+$ nix-shell -p 'idrisPackages.with-packages (with idrisPackages; [ contrib pruviloj ])'
+[nix-shell:~]$ idris -p contrib -p pruviloj
+```
+
+A listing of all available packages the Idris binary has access to is available via `--listlibs`:
+
+```
+$ idris --listlibs
+00prelude-idx.ibc
+pruviloj
+base
+contrib
+prelude
+00pruviloj-idx.ibc
+00base-idx.ibc
+00contrib-idx.ibc
+```
+
+## Building an Idris project with Nix
+
+As an example of how a Nix expression for an Idris package can be created, here is the one for `idrisPackages.yaml`:
+
+```nix
+{ build-idris-package
+, fetchFromGitHub
+, contrib
+, lightyear
+, lib
+}:
+build-idris-package  {
+  name = "yaml";
+  version = "2018-01-25";
+
+  # This is the .ipkg file that should be built, defaults to the package name
+  # In this case it should build `Yaml.ipkg` instead of `yaml.ipkg`
+  # This is only necessary because the yaml packages ipkg file is
+  # different from its package name here.
+  ipkgName = "Yaml";
+  # Idris dependencies to provide for the build
+  idrisDeps = [ contrib lightyear ];
+
+  src = fetchFromGitHub {
+    owner = "Heather";
+    repo = "Idris.Yaml";
+    rev = "5afa51ffc839844862b8316faba3bafa15656db4";
+    sha256 = "1g4pi0swmg214kndj85hj50ccmckni7piprsxfdzdfhg87s0avw7";
+  };
+
+  meta = {
+    description = "Idris YAML lib";
+    homepage = "https://github.com/Heather/Idris.Yaml";
+    license = lib.licenses.mit;
+    maintainers = [ lib.maintainers.brainrape ];
+  };
+}
+```
+
+Assuming this file is saved as `yaml.nix`, it's buildable using
+
+```
+$ nix-build -E '(import <nixpkgs> {}).idrisPackages.callPackage ./yaml.nix {}'
+```
+
+Or it's possible to use
+
+```nix
+with import <nixpkgs> {};
+
+{
+  yaml = idrisPackages.callPackage ./yaml.nix {};
+}
+```
+
+in another file (say `default.nix`) to be able to build it with
+
+```
+$ nix-build -A yaml
+```
+
+## Passing options to `idris` commands
+
+The `build-idris-package` function provides also optional input values to set additional options for the used `idris` commands.
+
+Specifically, you can set `idrisBuildOptions`, `idrisTestOptions`, `idrisInstallOptions` and `idrisDocOptions` to provide additional options to the `idris` command respectively when building, testing, installing and generating docs for your package.
+
+For example you could set
+
+```
+build-idris-package {
+  idrisBuildOptions = [ "--log" "1" "--verbose" ]
+
+  ...
+}
+```
+
+to require verbose output during `idris` build phase.

third_party/nixpkgs/doc/languages-frameworks/index.xml

@@ -0,0 +1,32 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-language-support">
+ <title>Languages and frameworks</title>
+ <para>
+  The <link linkend="chap-stdenv">standard build environment</link> makes it easy to build typical Autotools-based packages with very little code. Any other kind of package can be accomodated by overriding the appropriate phases of <literal>stdenv</literal>. However, there are specialised functions in Nixpkgs to easily build packages for other programming languages, such as Perl or Haskell. These are described in this chapter.
+ </para>
+ <xi:include href="android.section.xml" />
+ <xi:include href="beam.xml" />
+ <xi:include href="bower.xml" />
+ <xi:include href="coq.xml" />
+ <xi:include href="crystal.section.xml" />
+ <xi:include href="emscripten.section.xml" />
+ <xi:include href="gnome.xml" />
+ <xi:include href="go.xml" />
+ <xi:include href="haskell.section.xml" />
+ <xi:include href="idris.section.xml" />
+ <xi:include href="ios.section.xml" />
+ <xi:include href="java.xml" />
+ <xi:include href="lua.xml" />
+ <xi:include href="node.section.xml" />
+ <xi:include href="ocaml.xml" />
+ <xi:include href="perl.xml" />
+ <xi:include href="python.section.xml" />
+ <xi:include href="qt.xml" />
+ <xi:include href="r.section.xml" />
+ <xi:include href="ruby.xml" />
+ <xi:include href="rust.section.xml" />
+ <xi:include href="texlive.xml" />
+ <xi:include href="titanium.section.xml" />
+ <xi:include href="vim.section.xml" />
+</chapter>

third_party/nixpkgs/doc/languages-frameworks/ios.section.md

@@ -0,0 +1,229 @@
+---
+title: iOS
+author: Sander van der Burg
+date: 2019-11-10
+---
+# iOS
+
+This component is basically a wrapper/workaround that makes it possible to
+expose an Xcode installation as a Nix package by means of symlinking to the
+relevant executables on the host system.
+
+Since Xcode can't be packaged with Nix, nor we can publish it as a Nix package
+(because of its license) this is basically the only integration strategy
+making it possible to do iOS application builds that integrate with other
+components of the Nix ecosystem
+
+The primary objective of this project is to use the Nix expression language to
+specify how iOS apps can be built from source code, and to automatically spawn
+iOS simulator instances for testing.
+
+This component also makes it possible to use [Hydra](http://nixos.org/hydra),
+the Nix-based continuous integration server to regularly build iOS apps and to
+do wireless ad-hoc installations of enterprise IPAs on iOS devices through
+Hydra.
+
+The Xcode build environment implements a number of features.
+
+Deploying a proxy component wrapper exposing Xcode
+--------------------------------------------------
+The first use case is deploying a Nix package that provides symlinks to the Xcode
+installation on the host system. This package can be used as a build input to
+any build function implemented in the Nix expression language that requires
+Xcode.
+
+```nix
+let
+  pkgs = import <nixpkgs> {};
+
+  xcodeenv = import ./xcodeenv {
+    inherit (pkgs) stdenv;
+  };
+in
+xcodeenv.composeXcodeWrapper {
+  version = "9.2";
+  xcodeBaseDir = "/Applications/Xcode.app";
+}
+```
+
+By deploying the above expression with `nix-build` and inspecting its content
+you will notice that several Xcode-related executables are exposed as a Nix
+package:
+
+```bash
+$ ls result/bin
+lrwxr-xr-x  1 sander  staff  94  1 jan  1970 Simulator -> /Applications/Xcode.app/Contents/Developer/Applications/Simulator.app/Contents/MacOS/Simulator
+lrwxr-xr-x  1 sander  staff  17  1 jan  1970 codesign -> /usr/bin/codesign
+lrwxr-xr-x  1 sander  staff  17  1 jan  1970 security -> /usr/bin/security
+lrwxr-xr-x  1 sander  staff  21  1 jan  1970 xcode-select -> /usr/bin/xcode-select
+lrwxr-xr-x  1 sander  staff  61  1 jan  1970 xcodebuild -> /Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild
+lrwxr-xr-x  1 sander  staff  14  1 jan  1970 xcrun -> /usr/bin/xcrun
+```
+
+Building an iOS application
+---------------------------
+We can build an iOS app executable for the simulator, or an IPA/xcarchive file
+for release purposes, e.g. ad-hoc, enterprise or store installations, by
+executing the `xcodeenv.buildApp {}` function:
+
+```nix
+let
+  pkgs = import <nixpkgs> {};
+
+  xcodeenv = import ./xcodeenv {
+    inherit (pkgs) stdenv;
+  };
+in
+xcodeenv.buildApp {
+  name = "MyApp";
+  src = ./myappsources;
+  sdkVersion = "11.2";
+
+  target = null; # Corresponds to the name of the app by default
+  configuration = null; # Release for release builds, Debug for debug builds
+  scheme = null; # -scheme will correspond to the app name by default
+  sdk = null; # null will set it to 'iphonesimulator` for simulator builds or `iphoneos` to real builds
+  xcodeFlags = "";
+
+  release = true;
+  certificateFile = ./mycertificate.p12;
+  certificatePassword = "secret";
+  provisioningProfile = ./myprovisioning.profile;
+  signMethod = "ad-hoc"; # 'enterprise' or 'store'
+  generateIPA = true;
+  generateXCArchive = false;
+
+  enableWirelessDistribution = true;
+  installURL = "/installipa.php";
+  bundleId = "mycompany.myapp";
+  appVersion = "1.0";
+
+  # Supports all xcodewrapper parameters as well
+  xcodeBaseDir = "/Applications/Xcode.app";
+}
+```
+
+The above function takes a variety of parameters:
+* The `name` and `src` parameters are mandatory and specify the name of the app
+  and the location where the source code resides
+* `sdkVersion` specifies which version of the iOS SDK to use.
+
+It also possile to adjust the `xcodebuild` parameters. This is only needed in
+rare circumstances. In most cases the default values should suffice:
+
+* Specifies which `xcodebuild` target to build. By default it takes the target
+  that has the same name as the app.
+* The `configuration` parameter can be overridden if desired. By default, it
+  will do a debug build for the simulator and a release build for real devices.
+* The `scheme` parameter specifies which `-scheme` parameter to propagate to
+  `xcodebuild`. By default, it corresponds to the app name.
+* The `sdk` parameter specifies which SDK to use. By default, it picks
+  `iphonesimulator` for simulator builds and `iphoneos` for release builds.
+* The `xcodeFlags` parameter specifies arbitrary command line parameters that
+  should be propagated to `xcodebuild`.
+
+By default, builds are carried out for the iOS simulator. To do release builds
+(builds for real iOS devices), you must set the `release` parameter to `true`.
+In addition, you need to set the following parameters:
+
+* `certificateFile` refers to a P12 certificate file.
+* `certificatePassword` specifies the password of the P12 certificate.
+* `provisioningProfile` refers to the provision profile needed to sign the app
+* `signMethod` should refer to `ad-hoc` for signing the app with an ad-hoc
+  certificate, `enterprise` for enterprise certificates and `app-store` for App
+  store certificates.
+* `generateIPA` specifies that we want to produce an IPA file (this is probably
+  what you want)
+* `generateXCArchive` specifies thet we want to produce an xcarchive file.
+
+When building IPA files on Hydra and when it is desired to allow iOS devices to
+install IPAs by browsing to the Hydra build products page, you can enable the
+`enableWirelessDistribution` parameter.
+
+When enabled, you need to configure the following options:
+
+* The `installURL` parameter refers to the URL of a PHP script that composes the
+  `itms-services://` URL allowing iOS devices to install the IPA file.
+* `bundleId` refers to the bundle ID value of the app
+* `appVersion` refers to the app's version number
+
+To use wireless adhoc distributions, you must also install the corresponding
+PHP script on a web server (see section: 'Installing the PHP script for wireless
+ad hoc installations from Hydra' for more information).
+
+In addition to the build parameters, you can also specify any parameters that
+the `xcodeenv.composeXcodeWrapper {}` function takes. For example, the
+`xcodeBaseDir` parameter can be overridden to refer to a different Xcode
+version.
+
+Spawning simulator instances
+----------------------------
+In addition to building iOS apps, we can also automatically spawn simulator
+instances:
+
+```nix
+let
+  pkgs = import <nixpkgs> {};
+
+  xcodeenv = import ./xcodeenv {
+    inherit (pkgs) stdenv;
+  };
+in
+xcode.simulateApp {
+  name = "simulate";
+
+  # Supports all xcodewrapper parameters as well
+  xcodeBaseDir = "/Applications/Xcode.app";
+}
+```
+
+The above expression produces a script that starts the simulator from the
+provided Xcode installation. The script can be started as follows:
+
+```bash
+./result/bin/run-test-simulator
+```
+
+By default, the script will show an overview of UDID for all available simulator
+instances and asks you to pick one. You can also provide a UDID as a
+command-line parameter to launch an instance automatically:
+
+```bash
+./result/bin/run-test-simulator 5C93129D-CF39-4B1A-955F-15180C3BD4B8
+```
+
+You can also extend the simulator script to automatically deploy and launch an
+app in the requested simulator instance:
+
+```nix
+let
+  pkgs = import <nixpkgs> {};
+
+  xcodeenv = import ./xcodeenv {
+    inherit (pkgs) stdenv;
+  };
+in
+xcode.simulateApp {
+  name = "simulate";
+  bundleId = "mycompany.myapp";
+  app = xcode.buildApp {
+    # ...
+  };
+
+  # Supports all xcodewrapper parameters as well
+  xcodeBaseDir = "/Applications/Xcode.app";
+}
+```
+
+By providing the result of an `xcode.buildApp {}` function and configuring the
+app bundle id, the app gets deployed automatically and started.
+
+Troubleshooting
+---------------
+In some rare cases, it may happen that after a failure, changes are not picked
+up. Most likely, this is caused by a derived data cache that Xcode maintains.
+To wipe it you can run:
+
+```bash
+$ rm -rf ~/Library/Developer/Xcode/DerivedData
+```

third_party/nixpkgs/doc/languages-frameworks/java.xml

@@ -0,0 +1,63 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-java">
+ <title>Java</title>
+
+ <para>
+  Ant-based Java packages are typically built from source as follows:
+<programlisting>
+stdenv.mkDerivation {
+  name = "...";
+  src = fetchurl { ... };
+
+  nativeBuildInputs = [ jdk ant ];
+
+  buildPhase = "ant";
+}
+</programlisting>
+  Note that <varname>jdk</varname> is an alias for the OpenJDK (self-built where available, or pre-built via Zulu). Platforms with OpenJDK not (yet) in Nixpkgs (<literal>Aarch32</literal>, <literal>Aarch64</literal>) point to the (unfree) <literal>oraclejdk</literal>.
+ </para>
+
+ <para>
+  JAR files that are intended to be used by other packages should be installed in <filename>$out/share/java</filename>. JDKs have a stdenv setup hook that add any JARs in the <filename>share/java</filename> directories of the build inputs to the <envar>CLASSPATH</envar> environment variable. For instance, if the package <literal>libfoo</literal> installs a JAR named <filename>foo.jar</filename> in its <filename>share/java</filename> directory, and another package declares the attribute
+<programlisting>
+buildInputs = [ libfoo ];
+nativeBuildInputs = [ jdk ];
+</programlisting>
+  then <envar>CLASSPATH</envar> will be set to <filename>/nix/store/...-libfoo/share/java/foo.jar</filename>.
+ </para>
+
+ <para>
+  Private JARs should be installed in a location like <filename>$out/share/<replaceable>package-name</replaceable></filename>.
+ </para>
+
+ <para>
+  If your Java package provides a program, you need to generate a wrapper script to run it using the OpenJRE. You can use <literal>makeWrapper</literal> for this:
+<programlisting>
+nativeBuildInputs = [ makeWrapper ];
+
+installPhase =
+  ''
+    mkdir -p $out/bin
+    makeWrapper ${jre}/bin/java $out/bin/foo \
+      --add-flags "-cp $out/share/java/foo.jar org.foo.Main"
+  '';
+</programlisting>
+  Note the use of <literal>jre</literal>, which is the part of the OpenJDK package that contains the Java Runtime Environment. By using <literal>${jre}/bin/java</literal> instead of <literal>${jdk}/bin/java</literal>, you prevent your package from depending on the JDK at runtime.
+ </para>
+
+ <para>
+  Note all JDKs passthru <literal>home</literal>, so if your application requires environment variables like <envar>JAVA_HOME</envar> being set, that can be done in a generic fashion with the <literal>--set</literal> argument of <literal>makeWrapper</literal>:
+<programlisting>
+--set JAVA_HOME ${jdk.home}
+</programlisting>
+ </para>
+
+ <para>
+  It is possible to use a different Java compiler than <command>javac</command> from the OpenJDK. For instance, to use the GNU Java Compiler:
+<programlisting>
+nativeBuildInputs = [ gcj ant ];
+</programlisting>
+  Here, Ant will automatically use <command>gij</command> (the GNU Java Runtime) instead of the OpenJRE.
+ </para>
+</section>

third_party/nixpkgs/doc/languages-frameworks/lua.xml

@@ -0,0 +1,36 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-lua">
+ <title>Lua</title>
+
+ <para>
+  Lua packages are built by the <varname>buildLuaPackage</varname> function. This function is implemented in <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/lua-modules/generic/default.nix"> <filename>pkgs/development/lua-modules/generic/default.nix</filename></link> and works similarly to <varname>buildPerlPackage</varname>. (See <xref linkend="sec-language-perl"/> for details.)
+ </para>
+
+ <para>
+  Lua packages are defined in <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/lua-packages.nix"><filename>pkgs/top-level/lua-packages.nix</filename></link>. Most of them are simple. For example:
+<programlisting>
+fileSystem = buildLuaPackage {
+  name = "filesystem-1.6.2";
+  src = fetchurl {
+    url = "https://github.com/keplerproject/luafilesystem/archive/v1_6_2.tar.gz";
+    sha256 = "1n8qdwa20ypbrny99vhkmx8q04zd2jjycdb5196xdhgvqzk10abz";
+  };
+  meta = {
+    homepage = "https://github.com/keplerproject/luafilesystem";
+    hydraPlatforms = stdenv.lib.platforms.linux;
+    maintainers = with maintainers; [ flosse ];
+  };
+};
+</programlisting>
+ </para>
+
+ <para>
+  Though, more complicated package should be placed in a seperate file in <link
+  xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/lua-modules"><filename>pkgs/development/lua-modules</filename></link>.
+ </para>
+
+ <para>
+  Lua packages accept additional parameter <varname>disabled</varname>, which defines the condition of disabling package from luaPackages. For example, if package has <varname>disabled</varname> assigned to <literal>lua.luaversion != "5.1"</literal>, it will not be included in any luaPackages except lua51Packages, making it only be built for lua 5.1.
+ </para>
+</section>

third_party/nixpkgs/doc/languages-frameworks/node.section.md

@@ -0,0 +1,51 @@
+Node.js
+=======
+The `pkgs/development/node-packages` folder contains a generated collection of
+[NPM packages](https://npmjs.com/) that can be installed with the Nix package
+manager.
+
+As a rule of thumb, the package set should only provide *end user* software
+packages, such as command-line utilities. Libraries should only be added to the
+package set if there is a non-NPM package that requires it.
+
+When it is desired to use NPM libraries in a development project, use the
+`node2nix` generator directly on the `package.json` configuration file of the
+project.
+
+The package set also provides support for multiple Node.js versions. The policy
+is that a new package should be added to the collection for the latest stable LTS
+release (which is currently 10.x), unless there is an explicit reason to support
+a different release.
+
+If your package uses native addons, you need to examine what kind of native
+build system it uses. Here are some examples:
+
+* `node-gyp`
+* `node-gyp-builder`
+* `node-pre-gyp`
+
+After you have identified the correct system, you need to override your package
+expression while adding in build system as a build input. For example, `dat`
+requires `node-gyp-build`, so we override its expression in `default-v10.nix`:
+
+```nix
+dat = nodePackages.dat.override (oldAttrs: {
+  buildInputs = oldAttrs.buildInputs ++ [ nodePackages.node-gyp-build ];
+});
+```
+
+To add a package from NPM to nixpkgs:
+
+ 1. Modify `pkgs/development/node-packages/node-packages-v10.json` to add, update
+    or remove package entries. (Or `pkgs/development/node-packages/node-packages-v8.json`
+    for packages depending on Node.js 8.x)
+ 2. Run the script: `(cd pkgs/development/node-packages && ./generate.sh)`.
+ 3. Build your new package to test your changes:
+    `cd /path/to/nixpkgs && nix-build -A nodePackages.<new-or-updated-package>`.
+    To build against a specific Node.js version (e.g. 10.x):
+    `nix-build -A nodePackages_10_x.<new-or-updated-package>`
+ 4. Add and commit all modified and generated files.
+
+For more information about the generation process, consult the
+[README.md](https://github.com/svanderburg/node2nix) file of the `node2nix`
+tool.

third_party/nixpkgs/doc/languages-frameworks/ocaml.xml

@@ -0,0 +1,73 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-ocaml">
+ <title>OCaml</title>
+
+ <para>
+  OCaml libraries should be installed in <literal>$(out)/lib/ocaml/${ocaml.version}/site-lib/</literal>. Such directories are automatically added to the <literal>$OCAMLPATH</literal> environment variable when building another package that depends on them or when opening a <literal>nix-shell</literal>.
+ </para>
+
+ <para>
+  Given that most of the OCaml ecosystem is now built with dune, nixpkgs includes a convenience build support function called <literal>buildDunePackage</literal> that will build an OCaml package using dune, OCaml and findlib and any additional dependencies provided as <literal>buildInputs</literal> or <literal>propagatedBuildInputs</literal>.
+ </para>
+
+ <para>
+  Here is a simple package example. It defines an (optional) attribute <literal>minimumOCamlVersion</literal> that will be used to throw a descriptive evaluation error if building with an older OCaml is attempted. It uses the <literal>fetchFromGitHub</literal> fetcher to get its source. It sets the <literal>doCheck</literal> (optional) attribute to <literal>true</literal> which means that tests will be run with <literal>dune runtest -p angstrom</literal> after the build (<literal>dune build -p angstrom</literal>) is complete. It uses <literal>alcotest</literal> as a build input (because it is needed to run the tests) and <literal>bigstringaf</literal> and <literal>result</literal> as propagated build inputs (thus they will also be available to libraries depending on this library). The library will be installed using the <literal>angstrom.install</literal> file that dune generates.
+ </para>
+
+<programlisting>
+{ stdenv, fetchFromGitHub, buildDunePackage, alcotest, result, bigstringaf }:
+
+buildDunePackage rec {
+  pname = "angstrom";
+  version = "0.10.0";
+
+  minimumOCamlVersion = "4.03";
+
+  src = fetchFromGitHub {
+    owner  = "inhabitedtype";
+    repo   = pname;
+    rev    = version;
+    sha256 = "0lh6024yf9ds0nh9i93r9m6p5psi8nvrqxl5x7jwl13zb0r9xfpw";
+  };
+
+  buildInputs = [ alcotest ];
+  propagatedBuildInputs = [ bigstringaf result ];
+  doCheck = true;
+
+  meta = {
+    homepage = "https://github.com/inhabitedtype/angstrom";
+    description = "OCaml parser combinators built for speed and memory efficiency";
+    license = stdenv.lib.licenses.bsd3;
+    maintainers = with stdenv.lib.maintainers; [ sternenseemann ];
+  };
+}
+</programlisting>
+
+ <para>
+  Here is a second example, this time using a source archive generated with <literal>dune-release</literal>. It is a good idea to use this archive when it is available as it will usually contain substituted variables such as a <literal>%%VERSION%%</literal> field. This library does not depend on any other OCaml library and no tests are run after building it.
+ </para>
+
+<programlisting>
+{ stdenv, fetchurl, buildDunePackage }:
+
+buildDunePackage rec {
+  pname = "wtf8";
+  version = "1.0.1";
+
+  minimumOCamlVersion = "4.01";
+
+  src = fetchurl {
+    url = "https://github.com/flowtype/ocaml-${pname}/releases/download/v${version}/${pname}-${version}.tbz";
+    sha256 = "1msg3vycd3k8qqj61sc23qks541cxpb97vrnrvrhjnqxsqnh6ygq";
+  };
+
+  meta = with stdenv.lib; {
+    homepage = "https://github.com/flowtype/ocaml-wtf8";
+    description = "WTF-8 is a superset of UTF-8 that allows unpaired surrogates.";
+    license = licenses.mit;
+    maintainers = [ maintainers.eqyiel ];
+  };
+}
+</programlisting>
+</section>

third_party/nixpkgs/doc/languages-frameworks/perl.xml

@@ -0,0 +1,161 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-perl">
+ <title>Perl</title>
+
+ <para>
+  Nixpkgs provides a function <varname>buildPerlPackage</varname>, a generic package builder function for any Perl package that has a standard <varname>Makefile.PL</varname>. It’s implemented in <link
+xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/perl-modules/generic"><filename>pkgs/development/perl-modules/generic</filename></link>.
+ </para>
+
+ <para>
+  Perl packages from CPAN are defined in <link
+xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/perl-packages.nix"><filename>pkgs/top-level/perl-packages.nix</filename></link>, rather than <filename>pkgs/all-packages.nix</filename>. Most Perl packages are so straight-forward to build that they are defined here directly, rather than having a separate function for each package called from <filename>perl-packages.nix</filename>. However, more complicated packages should be put in a separate file, typically in <filename>pkgs/development/perl-modules</filename>. Here is an example of the former:
+<programlisting>
+ClassC3 = buildPerlPackage rec {
+  name = "Class-C3-0.21";
+  src = fetchurl {
+    url = "mirror://cpan/authors/id/F/FL/FLORA/${name}.tar.gz";
+    sha256 = "1bl8z095y4js66pwxnm7s853pi9czala4sqc743fdlnk27kq94gz";
+  };
+};
+</programlisting>
+  Note the use of <literal>mirror://cpan/</literal>, and the <literal>${name}</literal> in the URL definition to ensure that the name attribute is consistent with the source that we’re actually downloading. Perl packages are made available in <filename>all-packages.nix</filename> through the variable <varname>perlPackages</varname>. For instance, if you have a package that needs <varname>ClassC3</varname>, you would typically write
+<programlisting>
+foo = import ../path/to/foo.nix {
+  inherit stdenv fetchurl ...;
+  inherit (perlPackages) ClassC3;
+};
+</programlisting>
+  in <filename>all-packages.nix</filename>. You can test building a Perl package as follows:
+<screen>
+<prompt>$ </prompt>nix-build -A perlPackages.ClassC3
+</screen>
+  <varname>buildPerlPackage</varname> adds <literal>perl-</literal> to the start of the name attribute, so the package above is actually called <literal>perl-Class-C3-0.21</literal>. So to install it, you can say:
+<screen>
+<prompt>$ </prompt>nix-env -i perl-Class-C3
+</screen>
+  (Of course you can also install using the attribute name: <literal>nix-env -i -A perlPackages.ClassC3</literal>.)
+ </para>
+
+ <para>
+  So what does <varname>buildPerlPackage</varname> do? It does the following:
+  <orderedlist>
+   <listitem>
+    <para>
+     In the configure phase, it calls <literal>perl Makefile.PL</literal> to generate a Makefile. You can set the variable <varname>makeMakerFlags</varname> to pass flags to <filename>Makefile.PL</filename>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     It adds the contents of the <envar>PERL5LIB</envar> environment variable to <literal>#! .../bin/perl</literal> line of Perl scripts as <literal>-I<replaceable>dir</replaceable></literal> flags. This ensures that a script can find its dependencies. (This can cause this shebang line to become too long for Darwin to handle; see the note below.)
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     In the fixup phase, it writes the propagated build inputs (<varname>propagatedBuildInputs</varname>) to the file <filename>$out/nix-support/propagated-user-env-packages</filename>. <command>nix-env</command> recursively installs all packages listed in this file when you install a package that has it. This ensures that a Perl package can find its dependencies.
+    </para>
+   </listitem>
+  </orderedlist>
+ </para>
+
+ <para>
+  <varname>buildPerlPackage</varname> is built on top of <varname>stdenv</varname>, so everything can be customised in the usual way. For instance, the <literal>BerkeleyDB</literal> module has a <varname>preConfigure</varname> hook to generate a configuration file used by <filename>Makefile.PL</filename>:
+<programlisting>
+{ buildPerlPackage, fetchurl, db }:
+
+buildPerlPackage rec {
+  name = "BerkeleyDB-0.36";
+
+  src = fetchurl {
+    url = "mirror://cpan/authors/id/P/PM/PMQS/${name}.tar.gz";
+    sha256 = "07xf50riarb60l1h6m2dqmql8q5dij619712fsgw7ach04d8g3z1";
+  };
+
+  preConfigure = ''
+    echo "LIB = ${db.out}/lib" > config.in
+    echo "INCLUDE = ${db.dev}/include" >> config.in
+  '';
+}
+</programlisting>
+ </para>
+
+ <para>
+  Dependencies on other Perl packages can be specified in the <varname>buildInputs</varname> and <varname>propagatedBuildInputs</varname> attributes. If something is exclusively a build-time dependency, use <varname>buildInputs</varname>; if it’s (also) a runtime dependency, use <varname>propagatedBuildInputs</varname>. For instance, this builds a Perl module that has runtime dependencies on a bunch of other modules:
+<programlisting>
+ClassC3Componentised = buildPerlPackage rec {
+  name = "Class-C3-Componentised-1.0004";
+  src = fetchurl {
+    url = "mirror://cpan/authors/id/A/AS/ASH/${name}.tar.gz";
+    sha256 = "0xql73jkcdbq4q9m0b0rnca6nrlvf5hyzy8is0crdk65bynvs8q1";
+  };
+  propagatedBuildInputs = [
+    ClassC3 ClassInspector TestException MROCompat
+  ];
+};
+</programlisting>
+ </para>
+
+ <para>
+  On Darwin, if a script has too many <literal>-I<replaceable>dir</replaceable></literal> flags in its first line (its “shebang line”), it will not run. This can be worked around by calling the <literal>shortenPerlShebang</literal> function from the <literal>postInstall</literal> phase:
+<programlisting>
+{ stdenv, buildPerlPackage, fetchurl, shortenPerlShebang }:
+
+ImageExifTool = buildPerlPackage {
+  pname = "Image-ExifTool";
+  version = "11.50";
+
+  src = fetchurl {
+    url = "https://www.sno.phy.queensu.ca/~phil/exiftool/Image-ExifTool-11.50.tar.gz";
+    sha256 = "0d8v48y94z8maxkmw1rv7v9m0jg2dc8xbp581njb6yhr7abwqdv3";
+  };
+
+  buildInputs = stdenv.lib.optional stdenv.isDarwin shortenPerlShebang;
+  postInstall = stdenv.lib.optional stdenv.isDarwin ''
+    shortenPerlShebang $out/bin/exiftool
+  '';
+};
+</programlisting>
+  This will remove the <literal>-I</literal> flags from the shebang line, rewrite them in the <literal>use lib</literal> form, and put them on the next line instead. This function can be given any number of Perl scripts as arguments; it will modify them in-place.
+ </para>
+
+ <section xml:id="ssec-generation-from-CPAN">
+  <title>Generation from CPAN</title>
+
+  <para>
+   Nix expressions for Perl packages can be generated (almost) automatically from CPAN. This is done by the program <command>nix-generate-from-cpan</command>, which can be installed as follows:
+  </para>
+
+<screen>
+<prompt>$ </prompt>nix-env -i nix-generate-from-cpan
+</screen>
+
+  <para>
+   This program takes a Perl module name, looks it up on CPAN, fetches and unpacks the corresponding package, and prints a Nix expression on standard output. For example:
+<screen>
+<prompt>$ </prompt>nix-generate-from-cpan XML::Simple
+  XMLSimple = buildPerlPackage rec {
+    name = "XML-Simple-2.22";
+    src = fetchurl {
+      url = "mirror://cpan/authors/id/G/GR/GRANTM/${name}.tar.gz";
+      sha256 = "b9450ef22ea9644ae5d6ada086dc4300fa105be050a2030ebd4efd28c198eb49";
+    };
+    propagatedBuildInputs = [ XMLNamespaceSupport XMLSAX XMLSAXExpat ];
+    meta = {
+      description = "An API for simple XML files";
+      license = with stdenv.lib.licenses; [ artistic1 gpl1Plus ];
+    };
+  };
+</screen>
+   The output can be pasted into <filename>pkgs/top-level/perl-packages.nix</filename> or wherever else you need it.
+  </para>
+ </section>
+
+ <section xml:id="ssec-perl-cross-compilation">
+  <title>Cross-compiling modules</title>
+
+  <para>
+   Nixpkgs has experimental support for cross-compiling Perl modules. In many cases, it will just work out of the box, even for modules with native extensions. Sometimes, however, the Makefile.PL for a module may (indirectly) import a native module. In that case, you will need to make a stub for that module that will satisfy the Makefile.PL and install it into <filename>lib/perl5/site_perl/cross_perl/${perl.version}</filename>. See the <varname>postInstall</varname> for <varname>DBI</varname> for an example.
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/languages-frameworks/php.section.md

@@ -0,0 +1,112 @@
+# PHP
+
+## User Guide
+
+### Using PHP
+
+#### Overview
+
+Several versions of PHP are available on Nix, each of which having a
+wide variety of extensions and libraries available.
+
+The attribute `php` refers to the version of PHP considered most
+stable and thoroughly tested in nixpkgs for any given release of
+NixOS. Note that while this version of PHP may not be the latest major
+release from upstream, any version of PHP supported in nixpkgs may be
+utilized by specifying the desired attribute by version, such as
+`php74`.
+
+Only versions of PHP that are supported by upstream for the entirety
+of a given NixOS release will be included in that release of
+NixOS. See [PHP Supported
+Versions](https://www.php.net/supported-versions.php).
+
+Interactive tools built on PHP are put in `php.packages`; composer is
+for example available at `php.packages.composer`.
+
+Most extensions that come with PHP, as well as some popular
+third-party ones, are available in `php.extensions`; for example, the
+opcache extension shipped with PHP is available at
+`php.extensions.opcache` and the third-party ImageMagick extension at
+`php.extensions.imagick`.
+
+The different versions of PHP that nixpkgs provides is located under
+attributes named based on major and minor version number; e.g.,
+`php74` is PHP 7.4 with commonly used extensions installed,
+`php74base` is the same PHP runtime without extensions.
+
+#### Installing PHP with packages
+
+A PHP package with specific extensions enabled can be built using
+`php.withExtensions`. This is a function which accepts an anonymous
+function as its only argument; the function should take one argument,
+the set of all extensions, and return a list of wanted extensions. For
+example, a PHP package with the opcache and ImageMagick extensions
+enabled:
+
+```nix
+php.withExtensions (e: with e; [ imagick opcache ])
+```
+
+Note that this will give you a package with _only_ opcache and
+ImageMagick, none of the other extensions which are enabled by default
+in the `php` package will be available.
+
+To enable building on a previous PHP package, the currently enabled
+extensions are made available in its `enabledExtensions`
+attribute. For example, to generate a package with all default
+extensions enabled, except opcache, but with ImageMagick:
+
+```nix
+php.withExtensions (e:
+  (lib.filter (e: e != php.extensions.opcache) php.enabledExtensions)
+  ++ [ e.imagick ])
+```
+
+If you want a PHP build with extra configuration in the `php.ini`
+file, you can use `php.buildEnv`. This function takes two named and
+optional parameters: `extensions` and `extraConfig`. `extensions`
+takes an extension specification equivalent to that of
+`php.withExtensions`, `extraConfig` a string of additional `php.ini`
+configuration parameters. For example, a PHP package with the opcache
+and ImageMagick extensions enabled, and `memory_limit` set to `256M`:
+
+```nix
+php.buildEnv {
+  extensions = e: with e; [ imagick opcache ];
+  extraConfig = "memory_limit=256M";
+}
+```
+
+##### Example setup for `phpfpm`
+
+You can use the previous examples in a `phpfpm` pool called `foo` as
+follows:
+
+```nix
+let
+  myPhp = php.withExtensions (e: with e; [ imagick opcache ]);
+in {
+  services.phpfpm.pools."foo".phpPackage = myPhp;
+};
+```
+
+```nix
+let
+  myPhp = php.buildEnv {
+    extensions = e: with e; [ imagick opcache ];
+    extraConfig = "memory_limit=256M";
+  };
+in {
+  services.phpfpm.pools."foo".phpPackage = myPhp;
+};
+```
+
+##### Example usage with `nix-shell`
+
+This brings up a temporary environment that contains a PHP interpreter
+with the extensions `imagick` and `opcache` enabled.
+
+```sh
+nix-shell -p 'php.buildEnv { extensions = e: with e; [ imagick opcache ]; }'
+```

third_party/nixpkgs/doc/languages-frameworks/qt.xml

@@ -0,0 +1,149 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-qt">
+ <title>Qt</title>
+
+ <para>
+  This section describes the differences between Nix expressions for Qt libraries and applications and Nix expressions for other C++ software. Some knowledge of the latter is assumed. There are primarily two problems which the Qt infrastructure is designed to address: ensuring consistent versioning of all dependencies and finding dependencies at runtime.
+ </para>
+
+ <example xml:id='qt-default-nix'>
+  <title>Nix expression for a Qt package (<filename>default.nix</filename>)</title>
+<programlisting>
+{ mkDerivation, lib, qtbase }: <co xml:id='qt-default-nix-co-1' />
+
+mkDerivation { <co xml:id='qt-default-nix-co-2' />
+  pname = "myapp";
+  version = "1.0";
+
+  buildInputs = [ qtbase ]; <co xml:id='qt-default-nix-co-3' />
+}
+   </programlisting>
+ </example>
+
+ <calloutlist>
+  <callout arearefs='qt-default-nix-co-1'>
+   <para>
+    Import <literal>mkDerivation</literal> and Qt (such as <literal>qtbase</literal> modules directly. <emphasis>Do not</emphasis> import Qt package sets; the Qt versions of dependencies may not be coherent, causing build and runtime failures.
+   </para>
+  </callout>
+  <callout arearefs='qt-default-nix-co-2'>
+   <para>
+    Use <literal>mkDerivation</literal> instead of <literal>stdenv.mkDerivation</literal>. <literal>mkDerivation</literal> is a wrapper around <literal>stdenv.mkDerivation</literal> which applies some Qt-specific settings. This deriver accepts the same arguments as <literal>stdenv.mkDerivation</literal>; refer to <xref linkend='chap-stdenv' /> for details.
+   </para>
+   <para>
+    To use another deriver instead of <literal>stdenv.mkDerivation</literal>, use <literal>mkDerivationWith</literal>:
+<programlisting>
+mkDerivationWith myDeriver {
+  # ...
+}
+</programlisting>
+    If you cannot use <literal>mkDerivationWith</literal>, please refer to <xref linkend='qt-runtime-dependencies' />.
+   </para>
+  </callout>
+  <callout arearefs='qt-default-nix-co-3'>
+   <para>
+    <literal>mkDerivation</literal> accepts the same arguments as <literal>stdenv.mkDerivation</literal>, such as <literal>buildInputs</literal>.
+   </para>
+  </callout>
+ </calloutlist>
+
+ <formalpara xml:id='qt-runtime-dependencies'>
+  <title>Locating runtime dependencies</title>
+  <para>
+   Qt applications need to be wrapped to find runtime dependencies. If you cannot use <literal>mkDerivation</literal> or <literal>mkDerivationWith</literal> above, include <literal>wrapQtAppsHook</literal> in <literal>nativeBuildInputs</literal>:
+<programlisting>
+stdenv.mkDerivation {
+  # ...
+
+  nativeBuildInputs = [ wrapQtAppsHook ];
+}
+</programlisting>
+  </para>
+ </formalpara>
+
+ <para>
+  Entries added to <literal>qtWrapperArgs</literal> are used to modify the wrappers created by <literal>wrapQtAppsHook</literal>. The entries are passed as arguments to <xref linkend='fun-wrapProgram' />.
+<programlisting>
+mkDerivation {
+  # ...
+
+  qtWrapperArgs = [ ''--prefix PATH : /path/to/bin'' ];
+}
+</programlisting>
+ </para>
+
+ <para>
+  Set <literal>dontWrapQtApps</literal> to stop applications from being wrapped automatically. It is required to wrap applications manually with <literal>wrapQtApp</literal>, using the syntax of <xref linkend='fun-wrapProgram' />:
+<programlisting>
+mkDerivation {
+  # ...
+
+  dontWrapQtApps = true;
+  preFixup = ''
+      wrapQtApp "$out/bin/myapp" --prefix PATH : /path/to/bin
+  '';
+}
+</programlisting>
+ </para>
+
+ <note>
+  <para>
+   <literal>wrapQtAppsHook</literal> ignores files that are non-ELF executables. This means that scripts won't be automatically wrapped so you'll need to manually wrap them as previously mentioned. An example of when you'd always need to do this is with Python applications that use PyQT.
+  </para>
+ </note>
+
+ <para>
+  Libraries are built with every available version of Qt. Use the <literal>meta.broken</literal> attribute to disable the package for unsupported Qt versions:
+<programlisting>
+mkDerivation {
+  # ...
+
+  # Disable this library with Qt &lt; 5.9.0
+  meta.broken = builtins.compareVersions qtbase.version "5.9.0" &lt; 0;
+}
+</programlisting>
+ </para>
+
+ <formalpara>
+  <title>Adding a library to Nixpkgs</title>
+  <para>
+   Add a Qt library to <filename>all-packages.nix</filename> by adding it to the collection inside <literal>mkLibsForQt5</literal>. This ensures that the library is built with every available version of Qt as needed.
+   <example xml:id='qt-library-all-packages-nix'>
+    <title>Adding a Qt library to <filename>all-packages.nix</filename></title>
+<programlisting>
+{
+  # ...
+
+  mkLibsForQt5 = self: with self; {
+    # ...
+
+    mylib = callPackage ../path/to/mylib {};
+  };
+
+  # ...
+}
+</programlisting>
+   </example>
+  </para>
+ </formalpara>
+
+ <formalpara>
+  <title>Adding an application to Nixpkgs</title>
+  <para>
+   Add a Qt application to <filename>all-packages.nix</filename> using <literal>libsForQt5.callPackage</literal> instead of the usual <literal>callPackage</literal>. The former ensures that all dependencies are built with the same version of Qt.
+   <example xml:id='qt-application-all-packages-nix'>
+    <title>Adding a Qt application to <filename>all-packages.nix</filename></title>
+<programlisting>
+{
+  # ...
+
+  myapp = libsForQt5.callPackage ../path/to/myapp/ {};
+
+  # ...
+}
+</programlisting>
+   </example>
+  </para>
+ </formalpara>
+</section>

third_party/nixpkgs/doc/languages-frameworks/r.section.md

@@ -0,0 +1,120 @@
+R
+=
+
+## Installation
+
+Define an environment for R that contains all the libraries that you'd like to
+use by adding the following snippet to your $HOME/.config/nixpkgs/config.nix file:
+
+```nix
+{
+    packageOverrides = super: let self = super.pkgs; in
+    {
+
+        rEnv = super.rWrapper.override {
+            packages = with self.rPackages; [
+                devtools
+                ggplot2
+                reshape2
+                yaml
+                optparse
+                ];
+        };
+    };
+}
+```
+
+Then you can use `nix-env -f "<nixpkgs>" -iA rEnv` to install it into your user
+profile. The set of available libraries can be discovered by running the
+command `nix-env -f "<nixpkgs>" -qaP -A rPackages`. The first column from that
+output is the name that has to be passed to rWrapper in the code snipped above.
+
+However, if you'd like to add a file to your project source to make the
+environment available for other contributors, you can create a `default.nix`
+file like so:
+```nix
+let
+  pkgs = import <nixpkgs> {};
+  stdenv = pkgs.stdenv;
+in with pkgs; {
+  myProject = stdenv.mkDerivation {
+    name = "myProject";
+    version = "1";
+    src = if pkgs.lib.inNixShell then null else nix;
+
+    buildInputs = with rPackages; [
+      R
+      ggplot2
+      knitr
+    ];
+  };
+}
+```
+and then run `nix-shell .` to be dropped into a shell with those packages
+available.
+
+## RStudio
+
+RStudio uses a standard set of packages and ignores any custom R
+environments or installed packages you may have.  To create a custom
+environment, see `rstudioWrapper`, which functions similarly to
+`rWrapper`:
+
+```nix
+{
+    packageOverrides = super: let self = super.pkgs; in
+    {
+
+        rstudioEnv = super.rstudioWrapper.override {
+            packages = with self.rPackages; [
+                dplyr
+                ggplot2
+                reshape2
+                ];
+        };
+    };
+}
+```
+
+Then like above, `nix-env -f "<nixpkgs>" -iA rstudioEnv` will install
+this into your user profile.
+
+Alternatively, you can create a self-contained `shell.nix` without the need to
+modify any configuration files:
+
+```nix
+{ pkgs ? import <nixpkgs> {}
+}:
+
+pkgs.rstudioWrapper.override {
+  packages = with pkgs.rPackages; [ dplyr ggplot2 reshape2 ];
+}
+
+```
+
+Executing `nix-shell` will then drop you into an environment equivalent to the
+one above. If you need additional packages just add them to the list and
+re-enter the shell.
+
+## Updating the package set
+
+```bash
+nix-shell generate-shell.nix
+
+Rscript generate-r-packages.R cran  > cran-packages.nix.new
+mv cran-packages.nix.new cran-packages.nix
+
+Rscript generate-r-packages.R bioc  > bioc-packages.nix.new
+mv bioc-packages.nix.new bioc-packages.nix
+```
+
+`generate-r-packages.R <repo>` reads  `<repo>-packages.nix`, therefor the renaming.
+
+
+## Testing if the Nix-expression could be evaluated
+
+```bash
+nix-build test-evaluation.nix --dry-run
+```
+
+If this exits fine, the expression is ok. If not, you have to edit `default.nix`

third_party/nixpkgs/doc/languages-frameworks/ruby.section.md

@@ -0,0 +1,365 @@
+---
+title: Ruby
+author: Michael Fellinger
+date: 2019-05-23
+---
+
+# Ruby
+
+## User Guide
+
+### Using Ruby
+
+#### Overview
+
+Several versions of Ruby interpreters are available on Nix, as well as over 250 gems and many applications written in Ruby.
+The attribute `ruby` refers to the default Ruby interpreter, which is currently
+MRI 2.5. It's also possible to refer to specific versions, e.g. `ruby_2_6`, `jruby`, or `mruby`.
+
+In the nixpkgs tree, Ruby packages can be found throughout, depending on what
+they do, and are called from the main package set. Ruby gems, however are
+separate sets, and there's one default set for each interpreter (currently MRI
+only).
+
+There are two main approaches for using Ruby with gems.
+One is to use a specifically locked `Gemfile` for an application that has very strict dependencies.
+The other is to depend on the common gems, which we'll explain further down, and
+rely on them being updated regularly.
+
+The interpreters have common attributes, namely `gems`, and `withPackages`. So
+you can refer to `ruby.gems.nokogiri`, or `ruby_2_5.gems.nokogiri` to get the
+Nokogiri gem already compiled and ready to use.
+
+Since not all gems have executables like `nokogiri`, it's usually more
+convenient to use the `withPackages` function like this:
+`ruby.withPackages (p: with p; [ nokogiri ])`. This will also make sure that the
+Ruby in your environment will be able to find the gem and it can be used in your
+Ruby code (for example via `ruby` or `irb` executables) via `require "nokogiri"`
+as usual.
+
+#### Temporary Ruby environment with `nix-shell`
+
+Rather than having a single Ruby environment shared by all Ruby
+development projects on a system, Nix allows you to create separate
+environments per project.  `nix-shell` gives you the possibility to
+temporarily load another environment akin to a combined `chruby` or
+`rvm` and `bundle exec`.
+
+There are two methods for loading a shell with Ruby packages. The first and
+recommended method is to create an environment with `ruby.withPackages` and load
+that.
+
+```shell
+nix-shell -p "ruby.withPackages (ps: with ps; [ nokogiri pry ])"
+```
+
+The other method, which is not recommended, is to create an environment and list
+all the packages directly.
+
+```shell
+nix-shell -p ruby.gems.nokogiri ruby.gems.pry
+```
+
+Again, it's possible to launch the interpreter from the shell. The Ruby
+interpreter has the attribute `gems` which contains all Ruby gems for that
+specific interpreter.
+
+##### Load environment from `.nix` expression
+
+As explained in the Nix manual, `nix-shell` can also load an expression from a
+`.nix` file. Say we want to have Ruby 2.5, `nokogori`, and `pry`. Consider a
+`shell.nix` file with:
+
+```nix
+with import <nixpkgs> {};
+ruby.withPackages (ps: with ps; [ nokogiri pry ])
+```
+
+What's happening here?
+
+1. We begin with importing the Nix Packages collections. `import <nixpkgs>`
+   imports the `<nixpkgs>` function, `{}` calls it and the `with` statement
+   brings all attributes of `nixpkgs` in the local scope. These attributes form
+   the main package set.
+2. Then we create a Ruby environment with the `withPackages` function.
+3. The `withPackages` function expects us to provide a function as an argument
+   that takes the set of all ruby gems and returns a list of packages to include
+   in the environment. Here, we select the packages `nokogiri` and `pry` from
+   the package set.
+
+##### Execute command with `--run`
+
+A convenient flag for `nix-shell` is `--run`. It executes a command in the
+`nix-shell`. We can e.g. directly open a `pry` REPL:
+
+```shell
+nix-shell -p "ruby.withPackages (ps: with ps; [ nokogiri pry ])" --run "pry"
+```
+
+Or immediately require `nokogiri` in pry:
+
+```shell
+nix-shell -p "ruby.withPackages (ps: with ps; [ nokogiri pry ])" --run "pry -rnokogiri"
+```
+
+Or run a script using this environment:
+
+```shell
+nix-shell -p "ruby.withPackages (ps: with ps; [ nokogiri pry ])" --run "ruby example.rb"
+```
+
+##### Using `nix-shell` as shebang
+
+In fact, for the last case, there is a more convenient method. You can add a
+[shebang](https://en.wikipedia.org/wiki/Shebang_(Unix)) to your script
+specifying which dependencies `nix-shell` needs. With the following shebang, you
+can just execute `./example.rb`, and it will run with all dependencies.
+
+```ruby
+#! /usr/bin/env nix-shell
+#! nix-shell -i ruby -p "ruby.withPackages (ps: with ps; [ nokogiri rest-client ])"
+
+require 'nokogiri'
+require 'rest-client'
+
+body = RestClient.get('http://example.com').body
+puts Nokogiri::HTML(body).at('h1').text
+```
+
+### Developing with Ruby
+
+#### Using an existing Gemfile
+
+In most cases, you'll already have a `Gemfile.lock` listing all your dependencies.
+This can be used to generate a `gemset.nix` which is used to fetch the gems and
+combine them into a single environment.
+The reason why you need to have a separate file for this, is that Nix requires
+you to have a checksum for each input to your build.
+Since the `Gemfile.lock` that `bundler` generates doesn't provide us with
+checksums, we have to first download each gem, calculate its SHA256, and store
+it in this separate file.
+
+So the steps from having just a `Gemfile` to a `gemset.nix` are:
+
+```shell
+bundle lock
+bundix
+```
+
+If you already have a `Gemfile.lock`, you can simply run `bundix` and it will
+work the same.
+
+To update the gems in your `Gemfile.lock`, you may use the `bundix -l` flag,
+which will create a new `Gemfile.lock` in case the `Gemfile` has a more recent
+time of modification.
+
+Once the `gemset.nix` is generated, it can be used in a
+`bundlerEnv` derivation. Here is an example you could use for your `shell.nix`:
+
+```nix
+# ...
+let
+  gems = bundlerEnv {
+    name = "gems-for-some-project";
+    gemdir = ./.;
+  };
+in mkShell { buildInputs = [ gems gems.wrappedRuby ]; }
+```
+
+With this file in your directory, you can run `nix-shell` to build and use the gems.
+The important parts here are `bundlerEnv` and `wrappedRuby`.
+
+The `bundlerEnv` is a wrapper over all the gems in your gemset. This means that
+all the `/lib` and `/bin` directories will be available, and the executables of
+all gems (even of indirect dependencies) will end up in your `$PATH`.
+The `wrappedRuby` provides you with all executables that come with Ruby itself,
+but wrapped so they can easily find the gems in your gemset.
+
+One common issue that you might have is that you have Ruby 2.6, but also
+`bundler` in your gemset. That leads to a conflict for `/bin/bundle` and
+`/bin/bundler`. You can resolve this by wrapping either your Ruby or your gems
+in a `lowPrio` call. So in order to give the `bundler` from your gemset
+priority, it would be used like this:
+
+```nix
+# ...
+mkShell { buildInputs = [ gems (lowPrio gems.wrappedRuby) ]; }
+```
+
+
+#### Gem-specific configurations and workarounds
+
+In some cases, especially if the gem has native extensions, you might need to
+modify the way the gem is built.
+
+This is done via a common configuration file that includes all of the
+workarounds for each gem.
+
+This file lives at `/pkgs/development/ruby-modules/gem-config/default.nix`,
+since it already contains a lot of entries, it should be pretty easy to add the
+modifications you need for your needs.
+
+In the meanwhile, or if the modification is for a private gem, you can also add
+the configuration to only your own environment.
+
+Two places that allow this modification are the `ruby` derivation, or `bundlerEnv`.
+
+Here's the `ruby` one:
+
+```nix
+{ pg_version ? "10", pkgs ? import <nixpkgs> { } }:
+let
+  myRuby = pkgs.ruby.override {
+    defaultGemConfig = pkgs.defaultGemConfig // {
+      pg = attrs: {
+        buildFlags =
+        [ "--with-pg-config=${pkgs."postgresql_${pg_version}"}/bin/pg_config" ];
+      };
+    };
+  };
+in myRuby.withPackages (ps: with ps; [ pg ])
+```
+
+And an example with `bundlerEnv`:
+
+```nix
+{ pg_version ? "10", pkgs ? import <nixpkgs> { } }:
+let
+  gems = pkgs.bundlerEnv {
+    name = "gems-for-some-project";
+    gemdir = ./.;
+    gemConfig = pkgs.defaultGemConfig // {
+      pg = attrs: {
+        buildFlags =
+        [ "--with-pg-config=${pkgs."postgresql_${pg_version}"}/bin/pg_config" ];
+      };
+    };
+  };
+in mkShell { buildInputs = [ gems gems.wrappedRuby ]; }
+```
+
+And finally via overlays:
+
+```nix
+{ pg_version ? "10" }:
+let
+  pkgs = import <nixpkgs> {
+    overlays = [
+      (self: super: {
+        defaultGemConfig = super.defaultGemConfig // {
+          pg = attrs: {
+            buildFlags = [
+              "--with-pg-config=${
+                pkgs."postgresql_${pg_version}"
+              }/bin/pg_config"
+            ];
+          };
+        };
+      })
+    ];
+  };
+in pkgs.ruby.withPackages (ps: with ps; [ pg ])
+```
+
+Then we can get whichever postgresql version we desire and the `pg` gem will
+always reference it correctly:
+
+```shell
+$ nix-shell --argstr pg_version 9_4 --run 'ruby -rpg -e "puts PG.library_version"'
+90421
+
+$ nix-shell --run 'ruby -rpg -e "puts PG.library_version"'
+100007
+```
+
+Of course for this use-case one could also use overlays since the configuration
+for `pg` depends on the `postgresql` alias, but for demonstration purposes this
+has to suffice.
+
+#### Adding a gem to the default gemset
+
+Now that you know how to get a working Ruby environment with Nix, it's time to
+go forward and start actually developing with Ruby.
+We will first have a look at how Ruby gems are packaged on Nix. Then, we will
+look at how you can use development mode with your code.
+
+All gems in the standard set are automatically generated from a single
+`Gemfile`. The dependency resolution is done with `bundler` and makes it more
+likely that all gems are compatible to each other.
+
+In order to add a new gem to nixpkgs, you can put it into the
+`/pkgs/development/ruby-modules/with-packages/Gemfile` and run
+`./maintainers/scripts/update-ruby-packages`.
+
+To test that it works, you can then try using the gem with:
+
+```shell
+NIX_PATH=nixpkgs=$PWD nix-shell -p "ruby.withPackages (ps: with ps; [ name-of-your-gem ])"
+```
+
+#### Packaging applications
+
+A common task is to add a ruby executable to nixpkgs, popular examples would be
+`chef`, `jekyll`, or `sass`. A good way to do that is to use the `bundlerApp`
+function, that allows you to make a package that only exposes the listed
+executables, otherwise the package may cause conflicts through common paths like
+`bin/rake` or `bin/bundler` that aren't meant to be used.
+
+The absolute easiest way to do that is to write a
+`Gemfile` along these lines:
+
+```ruby
+source 'https://rubygems.org' do
+  gem 'mdl'
+end
+```
+
+If you want to package a specific version, you can use the standard Gemfile
+syntax for that, e.g. `gem 'mdl', '0.5.0'`, but if you want the latest stable
+version anyway, it's easier to update by simply running the `bundle lock` and
+`bundix` steps again.
+
+Now you can also also make a `default.nix` that looks like this:
+
+```nix
+{ lib, bundlerApp }:
+
+bundlerApp {
+  pname = "mdl";
+  gemdir = ./.;
+  exes = [ "mdl" ];
+}
+```
+
+All that's left to do is to generate the corresponding `Gemfile.lock` and
+`gemset.nix` as described above in the `Using an existing Gemfile` section.
+
+##### Packaging executables that require wrapping
+
+Sometimes your app will depend on other executables at runtime, and tries to
+find it through the `PATH` environment variable.
+
+In this case, you can provide a `postBuild` hook to `bundlerApp` that wraps the
+gem in another script that prefixes the `PATH`.
+
+Of course you could also make a custom `gemConfig` if you know exactly how to
+patch it, but it's usually much easier to maintain with a simple wrapper so the
+patch doesn't have to be adjusted for each version.
+
+Here's another example:
+
+```nix
+{ lib, bundlerApp, makeWrapper, git, gnutar, gzip }:
+
+bundlerApp {
+  pname = "r10k";
+  gemdir = ./.;
+  exes = [ "r10k" ];
+
+  buildInputs = [ makeWrapper ];
+
+  postBuild = ''
+    wrapProgram $out/bin/r10k --prefix PATH : ${lib.makeBinPath [ git gnutar gzip ]}
+  '';
+}
+```

third_party/nixpkgs/doc/languages-frameworks/ruby.xml

@@ -0,0 +1,108 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-ruby">
+ <title>Ruby</title>
+
+ <para>
+  There currently is support to bundle applications that are packaged as Ruby gems. The utility "bundix" allows you to write a <filename>Gemfile</filename>, let bundler create a <filename>Gemfile.lock</filename>, and then convert this into a nix expression that contains all Gem dependencies automatically.
+ </para>
+
+ <para>
+  For example, to package sensu, we did:
+ </para>
+
+<screen>
+<![CDATA[$ cd pkgs/servers/monitoring
+$ mkdir sensu
+$ cd sensu
+$ cat > Gemfile
+source 'https://rubygems.org'
+gem 'sensu'
+$ $(nix-build '<nixpkgs>' -A bundix --no-out-link)/bin/bundix --magic
+$ cat > default.nix
+{ lib, bundlerEnv, ruby }:
+
+bundlerEnv rec {
+  name = "sensu-${version}";
+
+  version = (import gemset).sensu.version;
+  inherit ruby;
+  # expects Gemfile, Gemfile.lock and gemset.nix in the same directory
+  gemdir = ./.;
+
+  meta = with lib; {
+    description = "A monitoring framework that aims to be simple, malleable, and scalable";
+    homepage    = "http://sensuapp.org/";
+    license     = with licenses; mit;
+    maintainers = with maintainers; [ theuni ];
+    platforms   = platforms.unix;
+  };
+}]]>
+</screen>
+
+ <para>
+  Please check in the <filename>Gemfile</filename>, <filename>Gemfile.lock</filename> and the <filename>gemset.nix</filename> so future updates can be run easily.
+ </para>
+
+ <para>
+  Updating Ruby packages can then be done like this:
+ </para>
+
+<screen>
+<![CDATA[$ cd pkgs/servers/monitoring/sensu
+$ nix-shell -p bundler --run 'bundle lock --update'
+$ nix-shell -p bundix --run 'bundix'
+]]>
+</screen>
+
+ <para>
+  For tools written in Ruby - i.e. where the desire is to install a package and then execute e.g. <command>rake</command> at the command line, there is an alternative builder called <literal>bundlerApp</literal>. Set up the <filename>gemset.nix</filename> the same way, and then, for example:
+ </para>
+
+<screen>
+<![CDATA[{ lib, bundlerApp }:
+
+bundlerApp {
+  pname = "corundum";
+  gemdir = ./.;
+  exes = [ "corundum-skel" ];
+
+  meta = with lib; {
+    description = "Tool and libraries for maintaining Ruby gems.";
+    homepage    = "https://github.com/nyarly/corundum";
+    license     = licenses.mit;
+    maintainers = [ maintainers.nyarly ];
+    platforms   = platforms.unix;
+  };
+}]]>
+</screen>
+
+ <para>
+  The chief advantage of <literal>bundlerApp</literal> over <literal>bundlerEnv</literal> is the executables introduced in the environment are precisely those selected in the <literal>exes</literal> list, as opposed to <literal>bundlerEnv</literal> which adds all the executables made available by gems in the gemset, which can mean e.g. <command>rspec</command> or <command>rake</command> in unpredictable versions available from various packages.
+ </para>
+
+ <para>
+  Resulting derivations for both builders also have two helpful attributes, <literal>env</literal> and <literal>wrappedRuby</literal>. The first one allows one to quickly drop into <command>nix-shell</command> with the specified environment present. E.g. <command>nix-shell -A sensu.env</command> would give you an environment with Ruby preset so it has all the libraries necessary for <literal>sensu</literal> in its paths. The second one can be used to make derivations from custom Ruby scripts which have <filename>Gemfile</filename>s with their dependencies specified. It is a derivation with <command>ruby</command> wrapped so it can find all the needed dependencies. For example, to make a derivation <literal>my-script</literal> for a <filename>my-script.rb</filename> (which should be placed in <filename>bin</filename>) you should run <command>bundix</command> as specified above and then use <literal>bundlerEnv</literal> like this:
+ </para>
+
+<programlisting>
+<![CDATA[let env = bundlerEnv {
+  name = "my-script-env";
+
+  inherit ruby;
+  gemfile = ./Gemfile;
+  lockfile = ./Gemfile.lock;
+  gemset = ./gemset.nix;
+};
+
+in stdenv.mkDerivation {
+  name = "my-script";
+  buildInputs = [ env.wrappedRuby ];
+  script = ./my-script.rb;
+  buildCommand = ''
+    install -D -m755 $script $out/bin/my-script
+    patchShebangs $out/bin/my-script
+  '';
+}]]>
+</programlisting>
+</section>

third_party/nixpkgs/doc/languages-frameworks/rust.section.md

@@ -0,0 +1,410 @@
+---
+title: Rust
+author: Matthias Beyer
+date: 2017-03-05
+---
+
+# Rust
+
+To install the rust compiler and cargo put
+
+```
+rustc
+cargo
+```
+
+into the `environment.systemPackages` or bring them into
+scope with `nix-shell -p rustc cargo`.
+
+For daily builds (beta and nightly) use either rustup from
+nixpkgs or use the [Rust nightlies
+overlay](#using-the-rust-nightlies-overlay).
+
+## Compiling Rust applications with Cargo
+
+Rust applications are packaged by using the `buildRustPackage` helper from `rustPlatform`:
+
+```
+rustPlatform.buildRustPackage rec {
+  pname = "ripgrep";
+  version = "11.0.2";
+
+  src = fetchFromGitHub {
+    owner = "BurntSushi";
+    repo = pname;
+    rev = version;
+    sha256 = "1iga3320mgi7m853la55xip514a3chqsdi1a1rwv25lr9b1p7vd3";
+  };
+
+  cargoSha256 = "17ldqr3asrdcsh4l29m3b5r37r5d0b3npq1lrgjmxb6vlx6a36qh";
+
+  meta = with stdenv.lib; {
+    description = "A fast line-oriented regex search tool, similar to ag and ack";
+    homepage = "https://github.com/BurntSushi/ripgrep";
+    license = licenses.unlicense;
+    maintainers = [ maintainers.tailhook ];
+    platforms = platforms.all;
+  };
+}
+```
+
+`buildRustPackage` requires a `cargoSha256` attribute which is computed over
+all crate sources of this package. Currently it is obtained by inserting a
+fake checksum into the expression and building the package once. The correct
+checksum can be then take from the failed build.
+
+Per the instructions in the [Cargo Book](https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html)
+best practices guide, Rust applications should always commit the `Cargo.lock`
+file in git to ensure a reproducible build. However, a few packages do not, and
+Nix depends on this file, so if it missing you can use `cargoPatches` to apply
+it in the `patchPhase`. Consider sending a PR upstream with a note to the
+maintainer describing why it's important to include in the application.
+
+The fetcher will verify that the `Cargo.lock` file is in sync with the `src`
+attribute, and fail the build if not. It will also will compress the vendor
+directory into a tar.gz archive.
+
+### Building a crate for a different target
+
+To build your crate with a different cargo `--target` simply specify the `target` attribute:
+
+```nix
+pkgs.rustPlatform.buildRustPackage {
+  (...)
+  target = "x86_64-fortanix-unknown-sgx";
+}
+```
+
+## Compiling Rust crates using Nix instead of Cargo
+
+### Simple operation
+
+When run, `cargo build` produces a file called `Cargo.lock`,
+containing pinned versions of all dependencies. Nixpkgs contains a
+tool called `carnix` (`nix-env -iA nixos.carnix`), which can be used
+to turn a `Cargo.lock` into a Nix expression.
+
+That Nix expression calls `rustc` directly (hence bypassing Cargo),
+and can be used to compile a crate and all its dependencies. Here is
+an example for a minimal `hello` crate:
+
+
+    $ cargo new hello
+    $ cd hello
+    $ cargo build
+     Compiling hello v0.1.0 (file:///tmp/hello)
+      Finished dev [unoptimized + debuginfo] target(s) in 0.20 secs
+    $ carnix -o hello.nix --src ./. Cargo.lock --standalone
+    $ nix-build hello.nix -A hello_0_1_0
+
+Now, the file produced by the call to `carnix`, called `hello.nix`, looks like:
+
+```
+# Generated by carnix 0.6.5: carnix -o hello.nix --src ./. Cargo.lock --standalone
+{ lib, stdenv, buildRustCrate, fetchgit }:
+let kernel = stdenv.buildPlatform.parsed.kernel.name;
+    # ... (content skipped)
+in
+rec {
+  hello = f: hello_0_1_0 { features = hello_0_1_0_features { hello_0_1_0 = f; }; };
+  hello_0_1_0_ = { dependencies?[], buildDependencies?[], features?[] }: buildRustCrate {
+    crateName = "hello";
+    version = "0.1.0";
+    authors = [ "pe@pijul.org <pe@pijul.org>" ];
+    src = ./.;
+    inherit dependencies buildDependencies features;
+  };
+  hello_0_1_0 = { features?(hello_0_1_0_features {}) }: hello_0_1_0_ {};
+  hello_0_1_0_features = f: updateFeatures f (rec {
+        hello_0_1_0.default = (f.hello_0_1_0.default or true);
+    }) [ ];
+}
+```
+
+In particular, note that the argument given as `--src` is copied
+verbatim to the source. If we look at a more complicated
+dependencies, for instance by adding a single line `libc="*"` to our
+`Cargo.toml`, we first need to run `cargo build` to update the
+`Cargo.lock`. Then, `carnix` needs to be run again, and produces the
+following nix file:
+
+```
+# Generated by carnix 0.6.5: carnix -o hello.nix --src ./. Cargo.lock --standalone
+{ lib, stdenv, buildRustCrate, fetchgit }:
+let kernel = stdenv.buildPlatform.parsed.kernel.name;
+    # ... (content skipped)
+in
+rec {
+  hello = f: hello_0_1_0 { features = hello_0_1_0_features { hello_0_1_0 = f; }; };
+  hello_0_1_0_ = { dependencies?[], buildDependencies?[], features?[] }: buildRustCrate {
+    crateName = "hello";
+    version = "0.1.0";
+    authors = [ "pe@pijul.org <pe@pijul.org>" ];
+    src = ./.;
+    inherit dependencies buildDependencies features;
+  };
+  libc_0_2_36_ = { dependencies?[], buildDependencies?[], features?[] }: buildRustCrate {
+    crateName = "libc";
+    version = "0.2.36";
+    authors = [ "The Rust Project Developers" ];
+    sha256 = "01633h4yfqm0s302fm0dlba469bx8y6cs4nqc8bqrmjqxfxn515l";
+    inherit dependencies buildDependencies features;
+  };
+  hello_0_1_0 = { features?(hello_0_1_0_features {}) }: hello_0_1_0_ {
+    dependencies = mapFeatures features ([ libc_0_2_36 ]);
+  };
+  hello_0_1_0_features = f: updateFeatures f (rec {
+    hello_0_1_0.default = (f.hello_0_1_0.default or true);
+    libc_0_2_36.default = true;
+  }) [ libc_0_2_36_features ];
+  libc_0_2_36 = { features?(libc_0_2_36_features {}) }: libc_0_2_36_ {
+    features = mkFeatures (features.libc_0_2_36 or {});
+  };
+  libc_0_2_36_features = f: updateFeatures f (rec {
+    libc_0_2_36.default = (f.libc_0_2_36.default or true);
+    libc_0_2_36.use_std =
+      (f.libc_0_2_36.use_std or false) ||
+      (f.libc_0_2_36.default or false) ||
+      (libc_0_2_36.default or false);
+  }) [];
+}
+```
+
+Here, the `libc` crate has no `src` attribute, so `buildRustCrate`
+will fetch it from [crates.io](https://crates.io). A `sha256`
+attribute is still needed for Nix purity.
+
+### Handling external dependencies
+
+Some crates require external libraries. For crates from
+[crates.io](https://crates.io), such libraries can be specified in
+`defaultCrateOverrides` package in nixpkgs itself.
+
+Starting from that file, one can add more overrides, to add features
+or build inputs by overriding the hello crate in a seperate file.
+
+```
+with import <nixpkgs> {};
+((import ./hello.nix).hello {}).override {
+  crateOverrides = defaultCrateOverrides // {
+    hello = attrs: { buildInputs = [ openssl ]; };
+  };
+}
+```
+
+Here, `crateOverrides` is expected to be a attribute set, where the
+key is the crate name without version number and the value a function.
+The function gets all attributes passed to `buildRustCrate` as first
+argument and returns a set that contains all attribute that should be
+overwritten.
+
+For more complicated cases, such as when parts of the crate's
+derivation depend on the crate's version, the `attrs` argument of
+the override above can be read, as in the following example, which
+patches the derivation:
+
+```
+with import <nixpkgs> {};
+((import ./hello.nix).hello {}).override {
+  crateOverrides = defaultCrateOverrides // {
+    hello = attrs: lib.optionalAttrs (lib.versionAtLeast attrs.version "1.0")  {
+      postPatch = ''
+        substituteInPlace lib/zoneinfo.rs \
+          --replace "/usr/share/zoneinfo" "${tzdata}/share/zoneinfo"
+      '';
+    };
+  };
+}
+```
+
+Another situation is when we want to override a nested
+dependency. This actually works in the exact same way, since the
+`crateOverrides` parameter is forwarded to the crate's
+dependencies. For instance, to override the build inputs for crate
+`libc` in the example above, where `libc` is a dependency of the main
+crate, we could do:
+
+```
+with import <nixpkgs> {};
+((import hello.nix).hello {}).override {
+  crateOverrides = defaultCrateOverrides // {
+    libc = attrs: { buildInputs = []; };
+  };
+}
+```
+
+### Options and phases configuration
+
+Actually, the overrides introduced in the previous section are more
+general. A number of other parameters can be overridden:
+
+- The version of rustc used to compile the crate:
+
+  ```
+  (hello {}).override { rust = pkgs.rust; };
+  ```
+
+- Whether to build in release mode or debug mode (release mode by
+  default):
+
+  ```
+  (hello {}).override { release = false; };
+  ```
+
+- Whether to print the commands sent to rustc when building
+  (equivalent to `--verbose` in cargo:
+
+  ```
+  (hello {}).override { verbose = false; };
+  ```
+
+- Extra arguments to be passed to `rustc`:
+
+  ```
+  (hello {}).override { extraRustcOpts = "-Z debuginfo=2"; };
+  ```
+
+- Phases, just like in any other derivation, can be specified using
+  the following attributes: `preUnpack`, `postUnpack`, `prePatch`,
+  `patches`, `postPatch`, `preConfigure` (in the case of a Rust crate,
+  this is run before calling the "build" script), `postConfigure`
+  (after the "build" script),`preBuild`, `postBuild`, `preInstall` and
+  `postInstall`. As an example, here is how to create a new module
+  before running the build script:
+
+  ```
+  (hello {}).override {
+    preConfigure = ''
+       echo "pub const PATH=\"${hi.out}\";" >> src/path.rs"
+    '';
+  };
+  ```
+
+### Features
+
+One can also supply features switches. For example, if we want to
+compile `diesel_cli` only with the `postgres` feature, and no default
+features, we would write:
+
+```
+(callPackage ./diesel.nix {}).diesel {
+  default = false;
+  postgres = true;
+}
+```
+
+Where `diesel.nix` is the file generated by Carnix, as explained above.
+
+
+## Setting Up `nix-shell`
+Oftentimes you want to develop code from within `nix-shell`. Unfortunately
+`buildRustCrate` does not support common `nix-shell` operations directly
+(see [this issue](https://github.com/NixOS/nixpkgs/issues/37945))
+so we will use `stdenv.mkDerivation` instead.
+
+Using the example `hello` project above, we want to do the following:
+- Have access to `cargo` and `rustc`
+- Have the `openssl` library available to a crate through it's _normal_
+  compilation mechanism (`pkg-config`).
+
+A typical `shell.nix` might look like:
+
+```
+with import <nixpkgs> {};
+
+stdenv.mkDerivation {
+  name = "rust-env";
+  nativeBuildInputs = [
+    rustc cargo
+
+    # Example Build-time Additional Dependencies
+    pkgconfig
+  ];
+  buildInputs = [
+    # Example Run-time Additional Dependencies
+    openssl
+  ];
+
+  # Set Environment Variables
+  RUST_BACKTRACE = 1;
+}
+```
+
+You should now be able to run the following:
+```
+$ nix-shell --pure
+$ cargo build
+$ cargo test
+```
+
+### Controlling Rust Version Inside `nix-shell`
+To control your rust version (i.e. use nightly) from within `shell.nix` (or
+other nix expressions) you can use the following `shell.nix`
+
+```
+# Latest Nightly
+with import <nixpkgs> {};
+let src = fetchFromGitHub {
+      owner = "mozilla";
+      repo = "nixpkgs-mozilla";
+      # commit from: 2019-05-15
+      rev = "9f35c4b09fd44a77227e79ff0c1b4b6a69dff533";
+      sha256 = "18h0nvh55b5an4gmlgfbvwbyqj91bklf1zymis6lbdh75571qaz0";
+   };
+in
+with import "${src.out}/rust-overlay.nix" pkgs pkgs;
+stdenv.mkDerivation {
+  name = "rust-env";
+  buildInputs = [
+    # Note: to use use stable, just replace `nightly` with `stable`
+    latest.rustChannels.nightly.rust
+
+    # Add some extra dependencies from `pkgs`
+    pkgconfig openssl
+  ];
+
+  # Set Environment Variables
+  RUST_BACKTRACE = 1;
+}
+```
+
+Now run:
+```
+$ rustc --version
+rustc 1.26.0-nightly (188e693b3 2018-03-26)
+```
+
+To see that you are using nightly.
+
+
+## Using the Rust nightlies overlay
+
+Mozilla provides an overlay for nixpkgs to bring a nightly version of Rust into scope.
+This overlay can _also_ be used to install recent unstable or stable versions
+of Rust, if desired.
+
+To use this overlay, clone
+[nixpkgs-mozilla](https://github.com/mozilla/nixpkgs-mozilla),
+and create a symbolic link to the file
+[rust-overlay.nix](https://github.com/mozilla/nixpkgs-mozilla/blob/master/rust-overlay.nix)
+in the `~/.config/nixpkgs/overlays` directory.
+
+    $ git clone https://github.com/mozilla/nixpkgs-mozilla.git
+    $ mkdir -p ~/.config/nixpkgs/overlays
+    $ ln -s $(pwd)/nixpkgs-mozilla/rust-overlay.nix ~/.config/nixpkgs/overlays/rust-overlay.nix
+
+The latest version can be installed with the following command:
+
+    $ nix-env -Ai nixos.latest.rustChannels.stable.rust
+
+Or using the attribute with nix-shell:
+
+    $ nix-shell -p nixos.latest.rustChannels.stable.rust
+
+To install the beta or nightly channel, "stable" should be substituted by
+"nightly" or "beta", or
+use the function provided by this overlay to pull a version based on a
+build date.
+
+The overlay automatically updates itself as it uses the same source as
+[rustup](https://www.rustup.rs/).

third_party/nixpkgs/doc/languages-frameworks/texlive.xml

@@ -0,0 +1,152 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="sec-language-texlive">
+ <title>TeX Live</title>
+
+ <para>
+  Since release 15.09 there is a new TeX Live packaging that lives entirely under attribute <varname>texlive</varname>.
+ </para>
+
+ <section xml:id="sec-language-texlive-users-guide">
+  <title>User's guide</title>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     For basic usage just pull <varname>texlive.combined.scheme-basic</varname> for an environment with basic LaTeX support.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     It typically won't work to use separately installed packages together. Instead, you can build a custom set of packages like this:
+<programlisting>
+texlive.combine {
+  inherit (texlive) scheme-small collection-langkorean algorithms cm-super;
+}
+</programlisting>
+     There are all the schemes, collections and a few thousand packages, as defined upstream (perhaps with tiny differences).
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     By default you only get executables and files needed during runtime, and a little documentation for the core packages. To change that, you need to add <varname>pkgFilter</varname> function to <varname>combine</varname>.
+<programlisting>
+texlive.combine {
+  # inherit (texlive) whatever-you-want;
+  pkgFilter = pkg:
+    pkg.tlType == "run" || pkg.tlType == "bin" || pkg.pname == "cm-super";
+  # elem tlType [ "run" "bin" "doc" "source" ]
+  # there are also other attributes: version, name
+}
+</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     You can list packages e.g. by <command>nix repl</command>.
+<programlisting><![CDATA[
+$ nix repl
+nix-repl> :l <nixpkgs>
+nix-repl> texlive.collection-<TAB>
+]]></programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Note that the wrapper assumes that the result has a chance to be useful. For example, the core executables should be present, as well as some core data files. The supported way of ensuring this is by including some scheme, for example <varname>scheme-basic</varname>, into the combination.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </section>
+
+ <section xml:id="sec-language-texlive-custom-packages">
+  <title>Custom packages</title>
+  <para>
+    You may find that you need to use an external TeX package. A derivation for such package has to provide contents of the "texmf" directory in its output and provide the <varname>tlType</varname> attribute. Here is a (very verbose) example:
+<programlisting><![CDATA[
+with import <nixpkgs> {};
+
+let
+  foiltex_run = stdenvNoCC.mkDerivation {
+    pname = "latex-foiltex";
+    version = "2.1.4b";
+    passthru.tlType = "run";
+
+    srcs = [
+      (fetchurl {
+        url = "http://mirrors.ctan.org/macros/latex/contrib/foiltex/foiltex.dtx";
+        sha256 = "07frz0krpz7kkcwlayrwrj2a2pixmv0icbngyw92srp9fp23cqpz";
+      })
+      (fetchurl {
+        url = "http://mirrors.ctan.org/macros/latex/contrib/foiltex/foiltex.ins";
+        sha256 = "09wkyidxk3n3zvqxfs61wlypmbhi1pxmjdi1kns9n2ky8ykbff99";
+      })
+    ];
+
+    unpackPhase = ''
+      runHook preUnpack
+
+      for _src in $srcs; do
+        cp "$_src" $(stripHash "$_src")
+      done
+
+      runHook postUnpack
+    '';
+
+    nativeBuildInputs = [ texlive.combined.scheme-small ];
+
+    dontConfigure = true;
+
+    buildPhase = ''
+      runHook preBuild
+
+      # Generate the style files
+      latex foiltex.ins
+
+      runHook postBuild
+    '';
+
+    installPhase = ''
+      runHook preInstall
+
+      path="$out/tex/latex/foiltex"
+      mkdir -p "$path"
+      cp *.{cls,def,clo} "$path/"
+
+      runHook postInstall
+    '';
+
+    meta = with lib; {
+      description = "A LaTeX2e class for overhead transparencies";
+      license = licenses.unfreeRedistributable;
+      maintainers = with maintainers; [ veprbl ];
+      platforms = platforms.all;
+    };
+  };
+  foiltex = { pkgs = [ foiltex_run ]; };
+
+  latex_with_foiltex = texlive.combine {
+    inherit (texlive) scheme-small;
+    inherit foiltex;
+  };
+in
+  runCommand "test.pdf" {
+    nativeBuildInputs = [ latex_with_foiltex ];
+  } ''
+cat >test.tex <<EOF
+\documentclass{foils}
+
+\title{Presentation title}
+\date{}
+
+\begin{document}
+\maketitle
+\end{document}
+EOF
+  pdflatex test.tex
+  cp test.pdf $out
+''
+]]></programlisting>
+  </para>
+ </section>
+</section>

third_party/nixpkgs/doc/languages-frameworks/titanium.section.md

@@ -0,0 +1,115 @@
+---
+title: Titanium
+author: Sander van der Burg
+date: 2018-11-18
+---
+# Titanium
+
+The Nixpkgs repository contains facilities to deploy a variety of versions of
+the [Titanium SDK](https://www.appcelerator.com) versions, a cross-platform
+mobile app development framework using JavaScript as an implementation language,
+and includes a function abstraction making it possible to build Titanium
+applications for Android and iOS devices from source code.
+
+Not all Titanium features supported -- currently, it can only be used to build
+Android and iOS apps.
+
+Building a Titanium app
+-----------------------
+We can build a Titanium app from source for Android or iOS and for debugging or
+release purposes by invoking the `titaniumenv.buildApp {}` function:
+
+```nix
+titaniumenv.buildApp {
+  name = "myapp";
+  src = ./myappsource;
+
+  preBuild = "";
+  target = "android"; # or 'iphone'
+  tiVersion = "7.1.0.GA";
+  release = true;
+
+  androidsdkArgs = {
+    platformVersions = [ "25" "26" ];
+  };
+  androidKeyStore = ./keystore;
+  androidKeyAlias = "myfirstapp";
+  androidKeyStorePassword = "secret";
+
+  xcodeBaseDir = "/Applications/Xcode.app";
+  xcodewrapperArgs = {
+    version = "9.3";
+  };
+  iosMobileProvisioningProfile = ./myprovisioning.profile;
+  iosCertificateName = "My Company";
+  iosCertificate = ./mycertificate.p12;
+  iosCertificatePassword = "secret";
+  iosVersion = "11.3";
+  iosBuildStore = false;
+
+  enableWirelessDistribution = true;
+  installURL = "/installipa.php";
+}
+```
+
+The `titaniumenv.buildApp {}` function takes the following parameters:
+
+* The `name` parameter refers to the name in the Nix store.
+* The `src` parameter refers to the source code location of the app that needs
+  to be built.
+* `preRebuild` contains optional build instructions that are carried out before
+  the build starts.
+* `target` indicates for which device the app must be built. Currently only
+  'android' and 'iphone' (for iOS) are supported.
+* `tiVersion` can be used to optionally override the requested Titanium version
+  in `tiapp.xml`. If not specified, it will use the version in `tiapp.xml`.
+* `release` should be set to true when building an app for submission to the
+  Google Playstore or Apple Appstore. Otherwise, it should be false.
+
+When the `target` has been set to `android`, we can configure the following
+parameters:
+
+* The `androidSdkArgs` parameter refers to an attribute set that propagates all
+  parameters to the `androidenv.composeAndroidPackages {}` function. This can
+  be used to install all relevant Android plugins that may be needed to perform
+  the Android build. If no parameters are given, it will deploy the platform
+  SDKs for API-levels 25 and 26 by default.
+
+When the `release` parameter has been set to true, you need to provide
+parameters to sign the app:
+
+* `androidKeyStore` is the path to the keystore file
+* `androidKeyAlias` is the key alias
+* `androidKeyStorePassword` refers to the password to open the keystore file.
+
+When the `target` has been set to `iphone`, we can configure the following
+parameters:
+
+* The `xcodeBaseDir` parameter refers to the location where Xcode has been
+  installed. When none value is given, the above value is the default.
+* The `xcodewrapperArgs` parameter passes arbitrary parameters to the
+  `xcodeenv.composeXcodeWrapper {}` function. This can, for example, be used
+  to adjust the default version of Xcode.
+
+When `release` has been set to true, you also need to provide the following
+parameters:
+
+* `iosMobileProvisioningProfile` refers to a mobile provisioning profile needed
+  for signing.
+* `iosCertificateName` refers to the company name in the P12 certificate.
+* `iosCertificate` refers to the path to the P12 file.
+* `iosCertificatePassword` contains the password to open the P12 file.
+* `iosVersion` refers to the iOS SDK version to use. It defaults to the latest
+  version.
+* `iosBuildStore` should be set to `true` when building for the Apple Appstore
+  submission. For enterprise or ad-hoc builds it should be set to `false`.
+
+When `enableWirelessDistribution` has been enabled, you must also provide the
+path of the PHP script (`installURL`) (that is included with the iOS build
+environment) to enable wireless ad-hoc installations.
+
+Emulating or simulating the app
+-------------------------------
+It is also possible to simulate the correspond iOS simulator build by using
+`xcodeenv.simulateApp {}` and emulate an Android APK by using
+`androidenv.emulateApp {}`.

third_party/nixpkgs/doc/languages-frameworks/vim.section.md

@@ -0,0 +1,272 @@
+---
+title: User's Guide for Vim in Nixpkgs
+author: Marc Weber
+date: 2016-06-25
+---
+# Vim
+
+Both Neovim and Vim can be configured to include your favorite plugins
+and additional libraries.
+
+Loading can be deferred; see examples.
+
+At the moment we support three different methods for managing plugins:
+
+- Vim packages (*recommend*)
+- VAM (=vim-addon-manager)
+- Pathogen
+- vim-plug
+
+## Custom configuration
+
+Adding custom .vimrc lines can be done using the following code:
+
+```nix
+vim_configurable.customize {
+  # `name` specifies the name of the executable and package
+  name = "vim-with-plugins";
+
+  vimrcConfig.customRC = ''
+    set hidden
+  '';
+}
+```
+
+This configuration is used when Vim is invoked with the command specified as name, in this case `vim-with-plugins`.
+
+For Neovim the `configure` argument can be overridden to achieve the same:
+
+```nix
+neovim.override {
+  configure = {
+    customRC = ''
+      # here your custom configuration goes!
+    '';
+  };
+}
+```
+
+If you want to use `neovim-qt` as a graphical editor, you can configure it by overriding Neovim in an overlay
+or passing it an overridden Neovimn:
+
+```nix
+neovim-qt.override {
+  neovim = neovim.override {
+    configure = {
+      customRC = ''
+        # your custom configuration
+      '';
+    };
+  };
+}
+```
+
+## Managing plugins with Vim packages
+
+To store you plugins in Vim packages (the native Vim plugin manager, see `:help packages`) the following example can be used:
+
+```nix
+vim_configurable.customize {
+  vimrcConfig.packages.myVimPackage = with pkgs.vimPlugins; {
+    # loaded on launch
+    start = [ youcompleteme fugitive ];
+    # manually loadable by calling `:packadd $plugin-name`
+    # however, if a Vim plugin has a dependency that is not explicitly listed in
+    # opt that dependency will always be added to start to avoid confusion.
+    opt = [ phpCompletion elm-vim ];
+    # To automatically load a plugin when opening a filetype, add vimrc lines like:
+    # autocmd FileType php :packadd phpCompletion
+  };
+}
+```
+
+`myVimPackage` is an arbitrary name for the generated package. You can choose any name you like.
+For Neovim the syntax is:
+
+```nix
+neovim.override {
+  configure = {
+    customRC = ''
+      # here your custom configuration goes!
+    '';
+    packages.myVimPackage = with pkgs.vimPlugins; {
+      # see examples below how to use custom packages
+      start = [ ];
+      # If a Vim plugin has a dependency that is not explicitly listed in
+      # opt that dependency will always be added to start to avoid confusion.
+      opt = [ ];
+    };
+  };
+}
+```
+
+The resulting package can be added to `packageOverrides` in `~/.nixpkgs/config.nix` to make it installable:
+
+```nix
+{
+  packageOverrides = pkgs: with pkgs; {
+    myVim = vim_configurable.customize {
+      # `name` specifies the name of the executable and package
+      name = "vim-with-plugins";
+      # add here code from the example section
+    };
+    myNeovim = neovim.override {
+      configure = {
+      # add here code from the example section
+      };
+    };
+  };
+}
+```
+
+After that you can install your special grafted `myVim` or `myNeovim` packages.
+
+## Managing plugins with vim-plug
+
+To use [vim-plug](https://github.com/junegunn/vim-plug) to manage your Vim
+plugins the following example can be used:
+
+```nix
+vim_configurable.customize {
+  vimrcConfig.packages.myVimPackage = with pkgs.vimPlugins; {
+    # loaded on launch
+    plug.plugins = [ youcompleteme fugitive phpCompletion elm-vim ];
+  };
+}
+```
+
+For Neovim the syntax is:
+
+```nix
+neovim.override {
+  configure = {
+    customRC = ''
+      # here your custom configuration goes!
+    '';
+    plug.plugins = with pkgs.vimPlugins; [
+      vim-go
+    ];
+  };
+}
+```
+
+## Managing plugins with VAM
+
+### Handling dependencies of Vim plugins
+
+VAM introduced .json files supporting dependencies without versioning
+assuming that "using latest version" is ok most of the time.
+
+### Example
+
+First create a vim-scripts file having one plugin name per line. Example:
+
+```
+"tlib"
+{'name': 'vim-addon-sql'}
+{'filetype_regex': '\%(vim)$', 'names': ['reload', 'vim-dev-plugin']}
+```
+
+Such vim-scripts file can be read by VAM as well like this:
+
+```vim
+call vam#Scripts(expand('~/.vim-scripts'), {})
+```
+
+Create a default.nix file:
+
+```nix
+{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc7102" }:
+nixpkgs.vim_configurable.customize { name = "vim"; vimrcConfig.vam.pluginDictionaries = [ "vim-addon-vim2nix" ]; }
+```
+
+Create a generate.vim file:
+
+```vim
+ActivateAddons vim-addon-vim2nix
+let vim_scripts = "vim-scripts"
+call nix#ExportPluginsForNix({
+\  'path_to_nixpkgs': eval('{"'.substitute(substitute(substitute($NIX_PATH, ':', ',', 'g'), '=',':', 'g'), '\([:,]\)', '"\1"',"g").'"}')["nixpkgs"],
+\  'cache_file': '/tmp/vim2nix-cache',
+\  'try_catch': 0,
+\  'plugin_dictionaries': ["vim-addon-manager"]+map(readfile(vim_scripts), 'eval(v:val)')
+\ })
+```
+
+Then run
+
+```bash
+nix-shell -p vimUtils.vim_with_vim2nix --command "vim -c 'source generate.vim'"
+```
+
+You should get a Vim buffer with the nix derivations (output1) and vam.pluginDictionaries (output2).
+You can add your Vim to your system's configuration file like this and start it by "vim-my":
+
+```
+my-vim =
+  let plugins = let inherit (vimUtils) buildVimPluginFrom2Nix; in {
+    copy paste output1 here
+  }; in vim_configurable.customize {
+    name = "vim-my";
+
+    vimrcConfig.vam.knownPlugins = plugins; # optional
+    vimrcConfig.vam.pluginDictionaries = [
+       copy paste output2 here
+    ];
+
+    # Pathogen would be
+    # vimrcConfig.pathogen.knownPlugins = plugins; # plugins
+    # vimrcConfig.pathogen.pluginNames = ["tlib"];
+  };
+```
+
+Sample output1:
+
+```
+"reload" = buildVimPluginFrom2Nix { # created by nix#NixDerivation
+  name = "reload";
+  src = fetchgit {
+    url = "git://github.com/xolox/vim-reload";
+    rev = "0a601a668727f5b675cb1ddc19f6861f3f7ab9e1";
+    sha256 = "0vb832l9yxj919f5hfg6qj6bn9ni57gnjd3bj7zpq7d4iv2s4wdh";
+  };
+  dependencies = ["nim-misc"];
+
+};
+[...]
+```
+
+Sample output2:
+
+```nix
+[
+  ''vim-addon-manager''
+  ''tlib''
+  { "name" = ''vim-addon-sql''; }
+  { "filetype_regex" = ''\%(vim)$$''; "names" = [ ''reload'' ''vim-dev-plugin'' ]; }
+]
+```
+
+## Adding new plugins to nixpkgs
+
+Nix expressions for Vim plugins are stored in [pkgs/misc/vim-plugins](/pkgs/misc/vim-plugins). For the vast majority of plugins, Nix expressions are automatically generated by running [`./update.py`](/pkgs/misc/vim-plugins/update.py). This creates a [generated.nix](/pkgs/misc/vim-plugins/generated.nix) file based on the plugins listed in [vim-plugin-names](/pkgs/misc/vim-plugins/vim-plugin-names). Plugins are listed in alphabetical order in `vim-plugin-names` using the format `[github username]/[repository]`. For example https://github.com/scrooloose/nerdtree becomes `scrooloose/nerdtree`.
+
+Some plugins require overrides in order to function properly. Overrides are placed in [overrides.nix](/pkgs/misc/vim-plugins/overrides.nix). Overrides are most often required when a plugin requires some dependencies, or extra steps are required during the build process. For example `deoplete-fish` requires both `deoplete-nvim` and `vim-fish`, and so the following override was added:
+
+```
+deoplete-fish = super.deoplete-fish.overrideAttrs(old: {
+  dependencies = with super; [ deoplete-nvim vim-fish ];
+});
+```
+
+Sometimes plugins require an override that must be changed when the plugin is updated. This can cause issues when Vim plugins are auto-updated but the associated override isn't updated. For these plugins, the override should be written so that it specifies all information required to install the plugin, and running `./update.py` doesn't change the derivation for the plugin. Manually updating the override is required to update these types of plugins. An example of such a plugin is `LanguageClient-neovim`.
+
+To add a new plugin, run `./update.py --add "[owner]/[name]"`. **NOTE**: This script automatically commits to your git repository. Be sure to check out a fresh branch before running.
+
+## Important repositories
+
+- [vim-pi](https://bitbucket.org/vimcommunity/vim-pi) is a plugin repository
+  from VAM plugin manager meant to be used by others as well used by
+
+- [vim2nix](https://github.com/MarcWeber/vim-addon-vim2nix) which generates the
+  .nix code

third_party/nixpkgs/doc/manual.xml

@@ -0,0 +1,41 @@
+<book xmlns="http://docbook.org/ns/docbook"
+      xmlns:xi="http://www.w3.org/2001/XInclude">
+ <info>
+  <title>Nixpkgs Users and Contributors Guide</title>
+  <subtitle>Version <xi:include href=".version" parse="text" />
+  </subtitle>
+ </info>
+ <xi:include href="preface.chapter.xml" />
+ <part>
+  <title>Using Nixpkgs</title>
+  <xi:include href="using/configuration.xml" />
+  <xi:include href="using/overlays.xml" />
+  <xi:include href="using/overrides.xml" />
+  <xi:include href="functions.xml" />
+ </part>
+ <part>
+  <title>Standard environment</title>
+  <xi:include href="stdenv/stdenv.xml" />
+  <xi:include href="stdenv/meta.xml" />
+  <xi:include href="stdenv/multiple-output.xml" />
+  <xi:include href="stdenv/cross-compilation.xml" />
+  <xi:include href="stdenv/platform-notes.xml" />
+ </part>
+ <part>
+  <title>Builders</title>
+  <xi:include href="builders/fetchers.xml" />
+  <xi:include href="builders/trivial-builders.xml" />
+  <xi:include href="builders/special.xml" />
+  <xi:include href="builders/images.xml" />
+  <xi:include href="languages-frameworks/index.xml" />
+  <xi:include href="builders/packages/index.xml" />
+ </part>
+ <part>
+  <title>Contributing to Nixpkgs</title>
+  <xi:include href="contributing/quick-start.xml" />
+  <xi:include href="contributing/coding-conventions.xml" />
+  <xi:include href="contributing/submitting-changes.xml" />
+  <xi:include href="contributing/reviewing-contributions.xml" />
+  <xi:include href="contributing/contributing-to-documentation.xml" />
+ </part>
+</book>

third_party/nixpkgs/doc/old/cross.txt

@@ -0,0 +1,329 @@
+Setting up a cross compiler with Nix
+
+"Cross compilation" means compiling a program on one machine for another
+type of machine. A typical use of cross compilation is to compile programs
+for embedded devices. These devices often don't have the computing power
+and memory to compile programs natively.
+
+For a fully working cross compiler the following are needed:
+
+* cross binutils: assembler, archiver, linker, etcetera that understand
+the format of the target system
+
+* cross compiler: a compiler that can generate binary code and object files
+for the target platform
+
+* cross C library: a library to link object files with to create fully
+functional programs
+
+Cross compilers are difficult to set up. A lot of people report that they
+cannot succeed in building a cross toolchain successfully. The answers
+usually consist of "download this pre-built toolchain", which is equally
+unhelpful.
+
+A toolchain is set up in five steps:
+
+1. build binutils to that can run on the host platform, but generate code
+for the target platform
+
+2. build Linux kernel headers for the target platform
+
+3. build a minimal C only version of GCC, that can run on the host platform
+and generate code for the target platform
+
+4. build a C library for the target platform. This includes the dynamic
+linker, C library, etc.
+
+5. build a full GCC
+
+****
+NB:
+
+Keep in mind that many programs are not very well suited for cross
+compilation. Either they are not intended to run on other platforms,
+because the code is highly platform specific, or the configuration process
+is not written with cross compilation in mind.
+
+Nix will not solve these problems for you!
+***
+
+This document describes to set up a cross compiler to generate code for
+arm-linux with uClibc and runs on i686-linux. The "stdenv" used is the
+default from the standard Nix packages collection.
+
+Step 1: build binutils for arm-linux in the stdenv for i686-linux
+
+---
+{stdenv, fetchurl, noSysDirs}:
+
+stdenv.mkDerivation {
+  name = "binutils-2.16.1-arm";
+  builder = ./builder.sh;
+  src = fetchurl {
+    url = "http://ftp.nluug.nl/gnu/binutils/binutils-2.16.1.tar.bz2";
+    sha256 = "1ian3kwh2vg6hr3ymrv48s04gijs539vzrq62xr76bxbhbwnz2np";
+  };
+  inherit noSysDirs;
+  configureFlags = [ "--target=arm-linux" ];
+}
+---
+
+This will compile binutils that will run on i686-linux, but knows the
+format used by arm-linux.
+
+Step 2: build kernel headers for the target architecture
+
+  default.nix for kernel-headers-arm:
+
+---
+{stdenv, fetchurl}:
+
+assert stdenv.buildPlatform.system == "i686-linux";
+
+stdenv.mkDerivation {
+  name = "linux-headers-2.6.13.1-arm";
+  builder = ./builder.sh;
+  src = fetchurl {
+    url = "http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.13.1.tar.bz2";
+    sha256 = "12qxmc827fjhaz53kjy7vyrzsaqcg78amiqsb3qm20z26w705lma";
+  };
+}
+---
+
+  builder.sh for kernel-headers-arm:
+
+---
+source $stdenv/setup
+
+
+buildPhase() {
+    make include/linux/version.h
+}
+
+buildPhase=buildPhase
+
+
+installPhase() {
+    mkdir $out
+    mkdir $out/include
+    #cd $out/include
+    #ln -s asm-arm asm
+    make include/asm ARCH=arm
+    cp -prvd include/linux include/asm include/asm-arm include/asm-generic $out/include
+    echo -n > $out/include/linux/autoconf.h
+}
+
+installPhase=installPhase
+
+
+genericBuild
+---
+
+Step 3: build a minimal GCC
+
+Extra/different parameters include the target platform and the kernel
+headers argument (this needs a major cleanup, as well as the name, it
+needs to be different!). Profiled compilers are disabled. The tarball
+used here is just gcc-core. For some reason it doesn't install nicely
+if the whole tarball is used (or is this some braino on my side? -- AH).
+
+Only C is used, because for other languages (such as C++) extra libraries
+need to be compiled, for which libraries compiled for the target system
+are needed.
+
+There is a bit of evilness going on. The cross compiled utilities need
+to be either copied to or be linked from the output tree of the compiler.
+(Is this really true? Back this up with arguments! -- AH)
+
+Symbolic links are not something we want inside the Nix store.
+
+---
+{ stdenv, fetchurl, noSysDirs
+, langC ? true, langCC ? true, langF77 ? false
+, profiledCompiler ? false
+, binutilsArm
+, kernelHeadersArm
+}:
+
+assert langC;
+
+stdenv.mkDerivation {
+  name = "gcc-4.0.2-arm";
+  builder = ./builder.sh;
+  src = fetchurl {
+    url = ftp://ftp.nluug.nl/pub/gnu/gcc/gcc-4.0.2/gcc-core-4.0.2.tar.bz2;
+    sha256 = "02fxh0asflm8825w23l2jq1wvs7hbnam0jayrivg7zdv2ifnc0rc";
+  };
+  # !!! apply only if noSysDirs is set
+  patches = [./no-sys-dirs.patch ./gcc-inhibit.patch];
+  inherit noSysDirs langC langCC langF77 profiledCompiler;
+  buildInputs = [binutilsArm];
+  inherit kernelHeadersArm binutilsArm;
+  platform = "arm-linux";
+}
+---
+
+The builder.sh for a cross-compiler. Note that the binutils are prefixed
+with the architecture name, so arm-linux-ld instead of ld, etc. This is
+necessary because when we cross-compile a lot of programs look for these
+tools with these specific names. The standard gcc-wrapper does not take this
+into account yet.
+
+---
+source $stdenv/setup
+
+
+export NIX_FIXINC_DUMMY=$NIX_BUILD_TOP/dummy
+mkdir $NIX_FIXINC_DUMMY
+
+
+if test "$noSysDirs" = "1"; then
+
+    if test "$noSysDirs" = "1"; then
+        # Figure out what extra flags to pass to the gcc compilers
+        # being generated to make sure that they use our glibc.
+        if test -e $NIX_CC/nix-support/orig-glibc; then
+            glibc=$(cat $NIX_CC/nix-support/orig-glibc)
+            # Ugh.  Copied from gcc-wrapper/builder.sh.  We can't just
+            # source in $NIX_CC/nix-support/add-flags, since that
+            # would cause *this* GCC to be linked against the
+            # *previous* GCC.  Need some more modularity there.
+            extraCFlags="-B$glibc/lib -isystem $glibc/include"
+            extraLDFlags="-B$glibc/lib -L$glibc/lib -Wl,-s \
+              -Wl,-dynamic-linker,$glibc/lib/ld-linux.so.2"
+
+            # Oh, what a hack.  I should be shot for this.
+            # In stage 1, we should link against the previous GCC, but
+            # not afterwards.  Otherwise we retain a dependency.
+            # However, ld-wrapper, which adds the linker flags for the
+            # previous GCC, is also used in stage 2/3.  We can prevent
+            # it from adding them by NIX_GLIBC_FLAGS_SET, but then
+            # gcc-wrapper will also not add them, thereby causing
+            # stage 1 to fail.  So we use a trick to only set the
+            # flags in gcc-wrapper.
+            hook=$(pwd)/ld-wrapper-hook
+            echo "NIX_GLIBC_FLAGS_SET=1" > $hook
+            export NIX_LD_WRAPPER_START_HOOK=$hook
+        fi
+
+        export NIX_EXTRA_CFLAGS=$extraCFlags
+        export NIX_EXTRA_LDFLAGS=$extraLDFlags
+        export CFLAGS=$extraCFlags
+        export CXXFLAGS=$extraCFlags
+        export LDFLAGS=$extraLDFlags
+    fi
+
+else
+    patches=""
+fi
+
+
+preConfigure=preConfigure
+preConfigure() {
+    
+    # Determine the frontends to build.
+    langs="c"
+    if test -n "$langCC"; then
+        langs="$langs,c++"
+    fi
+    if test -n "$langF77"; then
+        langs="$langs,f77"
+    fi
+
+    # Cross compiler evilness
+    mkdir -p $out
+    mkdir -p $out/arm-linux
+    mkdir -p $out/arm-linux/bin
+    ln -s $binutilsArm/arm-linux/bin/as $out/arm-linux/bin/as
+    ln -s $binutilsArm/arm-linux/bin/ld $out/arm-linux/bin/ld
+    ln -s $binutilsArm/arm-linux/bin/ar $out/arm-linux/bin/ar
+    ln -s $binutilsArm/arm-linux/bin/ranlib $out/arm-linux/bin/ranlib
+
+    # Perform the build in a different directory.
+    mkdir ../build
+    cd ../build
+
+    configureScript=../$sourceRoot/configure
+    configureFlags="--enable-languages=$langs --target=$platform --disable-threads --disable-libmudflap --disable-shared --with-headers=$kernelHeadersArm/include --disable-multilib"
+}
+
+
+postInstall=postInstall
+postInstall() {
+    # Remove precompiled headers for now.  They are very big and
+    # probably not very useful yet.
+    find $out/include -name "*.gch" -exec rm -rf {} \; -prune
+
+    # Remove `fixincl' to prevent a retained dependency on the
+    # previous gcc.
+    rm -rf $out/libexec/gcc/*/*/install-tools
+}
+
+
+#if test -z "$profiledCompiler"; then
+    #makeFlags="bootstrap"
+#else    
+    #makeFlags="profiledbootstrap"
+#fi
+
+genericBuild
+---
+
+Step 4: build a C library for the target platform.
+
+The previous steps are enough to compile a C library. In our case we take
+uClibc. It's intended to be a small sized replacement for glibc. It is widely
+used in embedded environments.
+
+...
+
+Step 5: Build a compiler to link with the newly built C library.
+
+...
+
+If we restrict the compiler to just C programs it is relatively easy,
+since we only need to wrap the GCC we built in the previous step with all
+the right tools and the right C library. Successfully compiled programs with
+this compiler and verified to be working on a HP Jornada 820 running Linux
+are "patch", "make" and "wget".
+
+If we want to build C++ programs it gets a lot more difficult. GCC has a
+three step compilation process. In the first step a simple compiler, called
+xgcc, that can compile only C programs is built. With that compiler it
+compiles itself two more times: one time to build a full compiler, and another
+time to build a full compiler once again with the freshly built compiler from
+step 2. In the second and third step support for C++ is compiled, if this
+is configured.
+
+One of the libraries that has to be built for C++ support step is libstdc++.
+This library uses xgcc, even when cross compiling, since libstdc++ has to be
+compiled for arm-linux.
+
+One of the compiler flags that GCC uses for this compiler is called X_CFLAGS.
+This is used by the Nix build process to set the dynamic linker, glibc
+in the case of i686-linux using the default Nix packages collection.
+
+Obiously, since we need to compile libstc++ for arm-linux with uClibc linking
+will not be done correctly: you can't link object files built for arm-linux
+with a glibc built for i686-linux.
+
+Setting X_CFLAGS to use the uClibc libraries and dynamic linker will fail
+too. Earlier on in the build process these flags are used to compile important
+files like libgcc.a by the host system gcc, which does need to be linked
+to glibc. To make this work correctly you will need to carefully juggle
+with compilation flags. This is still work in progress for Nix.
+
+
+---
+
+After successfully completing the whole toolchain you can start building
+packages with the newly built tools. To make everything build correctly
+you will need a stdenv for your target platform. Setting up this platform
+will take some effort. Right now there is a very experimental setup for
+arm-linux, which needs to be cleaned up before it is production ready.
+
+Please note that many packages are not well suited for cross-compilation.
+Even though the package itself might be very well portable often the
+buildscripts are not. One thing that we have seen that causes frequent
+build failures is the use of the LD variable. This is often set to 'ld'
+and not $(CROSS)-ld.

third_party/nixpkgs/doc/overrides.css

@@ -0,0 +1,22 @@
+.docbook .xref img[src^=images\/callouts\/],
+.screen img,
+.programlisting img,
+.literallayout img,
+.synopsis img {
+    width: 1em;
+}
+
+.calloutlist img {
+    width: 1.5em;
+}
+
+.prompt,
+.screen img,
+.programlisting img,
+.literallayout img,
+.synopsis img {
+    -moz-user-select: none;
+    -webkit-user-select: none;
+    -ms-user-select: none;
+    user-select: none;
+}

third_party/nixpkgs/doc/preface.chapter.md

@@ -0,0 +1,52 @@
+---
+title: Preface
+author: Frederik Rietdijk
+date: 2015-11-25
+---
+
+# Preface
+
+The Nix Packages collection (Nixpkgs) is a set of thousands of packages for the
+[Nix package manager](https://nixos.org/nix/), released under a
+[permissive MIT/X11 license](https://github.com/NixOS/nixpkgs/blob/master/COPYING).
+Packages are available for several platforms, and can be used with the Nix
+package manager on most GNU/Linux distributions as well as [NixOS](https://nixos.org/nixos).
+
+This manual primarily describes how to write packages for the Nix Packages collection
+(Nixpkgs). Thus it’s mainly for packagers and developers who want to add packages to
+Nixpkgs. If you like to learn more about the Nix package manager and the Nix
+expression language, then you are kindly referred to the [Nix manual](https://nixos.org/nix/manual/).
+The NixOS distribution is documented in the [NixOS manual](https://nixos.org/nixos/manual/).
+
+## Overview of Nixpkgs
+
+Nix expressions describe how to build packages from source and are collected in
+the [nixpkgs repository](https://github.com/NixOS/nixpkgs). Also included in the
+collection are Nix expressions for
+[NixOS modules](https://nixos.org/nixos/manual/index.html#sec-writing-modules).
+With these expressions the Nix package manager can build binary packages.
+
+Packages, including the Nix packages collection, are distributed through
+[channels](https://nixos.org/nix/manual/#sec-channels). The collection is
+distributed for users of Nix on non-NixOS distributions through the channel
+`nixpkgs`. Users of NixOS generally use one of the `nixos-*` channels, e.g.
+`nixos-19.09`, which includes all packages and modules for the stable NixOS
+19.09. Stable NixOS releases are generally only given
+security updates. More up to date packages and modules are available via the
+`nixos-unstable` channel.
+
+Both `nixos-unstable` and `nixpkgs` follow the `master` branch of the Nixpkgs
+repository, although both do lag the `master` branch by generally
+[a couple of days](https://status.nixos.org/). Updates to a channel are
+distributed as soon as all tests for that channel pass, e.g.
+[this table](https://hydra.nixos.org/job/nixpkgs/trunk/unstable#tabs-constituents)
+shows the status of tests for the `nixpkgs` channel.
+
+The tests are conducted by a cluster called [Hydra](http://nixos.org/hydra/),
+which also builds binary packages from the Nix expressions in Nixpkgs for
+`x86_64-linux`, `i686-linux` and `x86_64-darwin`.
+The binaries are made available via a [binary cache](https://cache.nixos.org).
+
+The current Nix expressions of the channels are available in the
+[`nixpkgs`](https://github.com/NixOS/nixpkgs) repository in branches
+that correspond to the channel names (e.g. `nixos-19.09-small`).

third_party/nixpkgs/doc/release-notes.xml

@@ -0,0 +1,650 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<article xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink">
+ <title>Nixpkgs Release Notes</title>
+ <section xml:id="release-notes-0.14">
+  <title>Release 0.14 (June 4, 2012)</title>
+
+  <para>
+   In preparation for the switch from Subversion to Git, this release is mainly the prevent the Nixpkgs version number from going backwards. (This would happen because prerelease version numbers produced for the Git repository are lower than those for the Subversion repository.)
+  </para>
+
+  <para>
+   Since the last release, there have been thousands of changes and new packages by numerous contributors. For details, see the commit logs.
+  </para>
+ </section>
+ <section xml:id="release-notes-0.13">
+  <title>Release 0.13 (February 5, 2010)</title>
+
+  <para>
+   As always, there are many changes. Some of the most important updates are:
+   <itemizedlist>
+    <listitem>
+     <para>
+      Glibc 2.9.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      GCC 4.3.3.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Linux 2.6.32.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      X.org 7.5.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      KDE 4.3.4.
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+ </section>
+ <section xml:id="release-notes-0.12">
+  <title>Release 0.12 (April 24, 2009)</title>
+
+  <para>
+   There are way too many additions to Nixpkgs since the last release to list here: for example, the number of packages on Linux has increased from 1002 to 2159. However, some specific improvements are worth listing:
+   <itemizedlist>
+    <listitem>
+     <para>
+      Nixpkgs now has a manual. In particular, it describes the standard build environment in detail.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Major new packages:
+      <itemizedlist>
+       <listitem>
+        <para>
+         KDE 4.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         TeXLive.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         VirtualBox.
+        </para>
+       </listitem>
+      </itemizedlist>
+      … and many others.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Important updates:
+      <itemizedlist>
+       <listitem>
+        <para>
+         Glibc 2.7.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         GCC 4.2.4.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Linux 2.6.25 — 2.6.28.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Firefox 3.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         X.org 7.3.
+        </para>
+       </listitem>
+      </itemizedlist>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Support for building derivations in a virtual machine, including RPM and Debian builds in automatically generated VM images. See <filename>pkgs/build-support/vm/default.nix</filename> for details.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Improved support for building Haskell packages.
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+
+  <para>
+   The following people contributed to this release: Andres Löh, Arie Middelkoop, Armijn Hemel, Eelco Dolstra, Lluís Batlle, Ludovic Courtès, Marc Weber, Mart Kolthof, Martin Bravenboer, Michael Raskin, Nicolas Pierron, Peter Simons, Pjotr Prins, Rob Vermaas, Sander van der Burg, Tobias Hammerschmidt, Valentin David, Wouter den Breejen and Yury G. Kudryashov. In addition, several people contributed patches on the <literal>nix-dev</literal> mailing list.
+  </para>
+ </section>
+ <section xml:id="release-notes-0.11">
+  <title>Release 0.11 (September 11, 2007)</title>
+
+  <para>
+   This release has the following improvements:
+   <itemizedlist>
+    <listitem>
+     <para>
+      The standard build environment (<literal>stdenv</literal>) is now pure on the <literal>x86_64-linux</literal> and <literal>powerpc-linux</literal> platforms, just as on <literal>i686-linux</literal>. (Purity means that building and using the standard environment has no dependencies outside of the Nix store. For instance, it doesn’t require an external C compiler such as <filename>/usr/bin/gcc</filename>.) Also, the statically linked binaries used in the bootstrap process are now automatically reproducible, making it easy to update the bootstrap tools and to add support for other Linux platforms. See <filename>pkgs/stdenv/linux/make-bootstrap-tools.nix</filename> for details.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Hook variables in the generic builder are now executed using the <function>eval</function> shell command. This has a major advantage: you can write hooks directly in Nix expressions. For instance, rather than writing a builder like this:
+<programlisting>
+source $stdenv/setup
+
+postInstall=postInstall
+postInstall() {
+    ln -sf gzip $out/bin/gunzip
+    ln -sf gzip $out/bin/zcat
+}
+
+genericBuild</programlisting>
+      (the <literal>gzip</literal> builder), you can just add this attribute to the derivation:
+<programlisting>
+postInstall = "ln -sf gzip $out/bin/gunzip; ln -sf gzip $out/bin/zcat";</programlisting>
+      and so a separate build script becomes unnecessary. This should allow us to get rid of most builders in Nixpkgs.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      It is now possible to have the generic builder pass arguments to <command>configure</command> and <command>make</command> that contain whitespace. Previously, for example, you could say in a builder,
+<programlisting>
+configureFlags="CFLAGS=-O0"</programlisting>
+      but not
+<programlisting>
+configureFlags="CFLAGS=-O0 -g"</programlisting>
+      since the <literal>-g</literal> would be interpreted as a separate argument to <command>configure</command>. Now you can say
+<programlisting>
+configureFlagsArray=("CFLAGS=-O0 -g")</programlisting>
+      or similarly
+<programlisting>
+configureFlagsArray=("CFLAGS=-O0 -g" "LDFLAGS=-L/foo -L/bar")</programlisting>
+      which does the right thing. Idem for <literal>makeFlags</literal>, <literal>installFlags</literal>, <literal>checkFlags</literal> and <literal>distFlags</literal>.
+     </para>
+     <para>
+      Unfortunately you can't pass arrays to Bash through the environment, so you can't put the array above in a Nix expression, e.g.,
+<programlisting>
+configureFlagsArray = ["CFLAGS=-O0 -g"];</programlisting>
+      since it would just be flattened to a since string. However, you <emphasis>can</emphasis> use the inline hooks described above:
+<programlisting>
+preConfigure = "configureFlagsArray=(\"CFLAGS=-O0 -g\")";</programlisting>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      The function <function>fetchurl</function> now has support for two different kinds of mirroring of files. First, it has support for <emphasis>content-addressable mirrors</emphasis>. For example, given the <function>fetchurl</function> call
+<programlisting>
+fetchurl {
+  url = "http://releases.mozilla.org/<replaceable>...</replaceable>/firefox-2.0.0.6-source.tar.bz2";
+  sha1 = "eb72f55e4a8bf08e8c6ef227c0ade3d068ba1082";
+}</programlisting>
+      <function>fetchurl</function> will first try to download this file from <link
+  xlink:href="http://tarballs.nixos.org/sha1/eb72f55e4a8bf08e8c6ef227c0ade3d068ba1082"/>. If that file doesn’t exist, it will try the original URL. In general, the “content-addressed” location is <replaceable>mirror</replaceable><literal>/</literal><replaceable>hash-type</replaceable><literal>/</literal><replaceable>hash</replaceable>. There is currently only one content-addressable mirror (<link
+  xlink:href="http://tarballs.nixos.org"/>), but more can be specified in the <varname>hashedMirrors</varname> attribute in <filename>pkgs/build-support/fetchurl/mirrors.nix</filename>, or by setting the <envar>NIX_HASHED_MIRRORS</envar> environment variable to a whitespace-separated list of URLs.
+     </para>
+     <para>
+      Second, <function>fetchurl</function> has support for widely-mirrored distribution sites such as SourceForge or the Linux kernel archives. Given a URL of the form <literal>mirror://<replaceable>site</replaceable>/<replaceable>path</replaceable></literal>, it will try to download <replaceable>path</replaceable> from a configurable list of mirrors for <replaceable>site</replaceable>. (This idea was borrowed from Gentoo Linux.) Example:
+<programlisting>
+fetchurl {
+  url = mirror://gnu/gcc/gcc-4.2.0/gcc-core-4.2.0.tar.bz2;
+  sha256 = "0ykhzxhr8857dr97z0j9wyybfz1kjr71xk457cfapfw5fjas4ny1";
+}</programlisting>
+      Currently <replaceable>site</replaceable> can be <literal>sourceforge</literal>, <literal>gnu</literal> and <literal>kernel</literal>. The list of mirrors is defined in <filename>pkgs/build-support/fetchurl/mirrors.nix</filename>. You can override the list of mirrors for a particular site by setting the environment variable <envar>NIX_MIRRORS_<replaceable>site</replaceable></envar>, e.g.
+<programlisting>
+export NIX_MIRRORS_sourceforge=http://osdn.dl.sourceforge.net/sourceforge/</programlisting>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Important updates:
+      <itemizedlist>
+       <listitem>
+        <para>
+         Glibc 2.5.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         GCC 4.1.2.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Gnome 2.16.3.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         X11R7.2.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Linux 2.6.21.7 and 2.6.22.6.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Emacs 22.1.
+        </para>
+       </listitem>
+      </itemizedlist>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Major new packages:
+      <itemizedlist>
+       <listitem>
+        <para>
+         KDE 3.5.6 Base.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Wine 0.9.43.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         OpenOffice 2.2.1.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Many Linux system packages to support NixOS.
+        </para>
+       </listitem>
+      </itemizedlist>
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+
+  <para>
+   The following people contributed to this release: Andres Löh, Arie Middelkoop, Armijn Hemel, Eelco Dolstra, Marc Weber, Mart Kolthof, Martin Bravenboer, Michael Raskin, Wouter den Breejen and Yury G. Kudryashov.
+  </para>
+ </section>
+ <section xml:id="release-notes-0.10">
+  <title>Release 0.10 (October 12, 2006)</title>
+
+  <note>
+   <para>
+    This release of Nixpkgs requires <link
+xlink:href='http://nixos.org/releases/nix/nix-0.10/'>Nix 0.10</link> or higher.
+   </para>
+  </note>
+
+  <para>
+   This release has the following improvements:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     <filename>pkgs/system/all-packages-generic.nix</filename> is gone, we now just have <filename>pkgs/top-level/all-packages.nix</filename> that contains all available packages. This should cause much less confusion with users. <filename>all-packages.nix</filename> is a function that by default returns packages for the current platform, but you can override this by specifying a different <varname>system</varname> argument.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Certain packages in Nixpkgs are now user-configurable through a configuration file, i.e., without having to edit the Nix expressions in Nixpkgs. For instance, the Firefox provided in the Nixpkgs channel is built without the RealPlayer plugin (for legal reasons). Previously, you could easily enable RealPlayer support by editing the call to the Firefox function in <filename>all-packages.nix</filename>, but such changes are not respected when Firefox is subsequently updated through the Nixpkgs channel.
+    </para>
+    <para>
+     The Nixpkgs configuration file (found in <filename>~/.nixpkgs/config.nix</filename> or through the <envar>NIXPKGS_CONFIG</envar> environment variable) is an attribute set that contains configuration options that <filename>all-packages.nix</filename> reads and uses for certain packages. For instance, the following configuration file:
+<programlisting>
+{
+  firefox = {
+    enableRealPlayer = true;
+  };
+}</programlisting>
+     persistently enables RealPlayer support in the Firefox build.
+    </para>
+    <para>
+     (Actually, <literal>firefox.enableRealPlayer</literal> is the <emphasis>only</emphasis> configuration option currently available, but more are sure to be added.)
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Support for new platforms:
+     <itemizedlist>
+      <listitem>
+       <para>
+        <literal>i686-cygwin</literal>, i.e., Windows (using <link xlink:href="http://www.cygwin.com/">Cygwin</link>). The standard environment on <literal>i686-cygwin</literal> by default builds binaries for the Cygwin environment (i.e., it uses Cygwin tools and produces executables that use the Cygwin library). However, there is also a standard environment that produces binaries that use <link
+      xlink:href="http://www.mingw.org/">MinGW</link>. You can use it by calling <filename>all-package.nix</filename> with the <varname>stdenvType</varname> argument set to <literal>"i686-mingw"</literal>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <literal>i686-darwin</literal>, i.e., Mac OS X on Intel CPUs.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <literal>powerpc-linux</literal>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <literal>x86_64-linux</literal>, i.e., Linux on 64-bit AMD/Intel CPUs. Unlike <literal>i686-linux</literal>, this platform doesn’t have a pure <literal>stdenv</literal> yet.
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The default compiler is now GCC 4.1.1.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     X11 updated to X.org’s X11R7.1.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Notable new packages:
+     <itemizedlist>
+      <listitem>
+       <para>
+        Opera.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Microsoft Visual C++ 2005 Express Edition and the Windows SDK.
+       </para>
+      </listitem>
+     </itemizedlist>
+     In total there are now around 809 packages in Nixpkgs.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     It is now <emphasis>much</emphasis> easier to override the default C compiler and other tools in <literal>stdenv</literal> for specific packages. <filename>all-packages.nix</filename> provides two utility functions for this purpose: <function>overrideGCC</function> and <function>overrideInStdenv</function>. Both take a <literal>stdenv</literal> and return an augmented <literal>stdenv</literal>; the formed changes the C compiler, and the latter adds additional packages to the front of <literal>stdenv</literal>’s initial <envar>PATH</envar>, allowing tools to be overridden.
+    </para>
+    <para>
+     For instance, the package <varname>strategoxt</varname> doesn’t build with the GNU Make in <literal>stdenv</literal> (version 3.81), so we call it with an augmented <literal>stdenv</literal> that uses GNU Make 3.80:
+<programlisting>
+strategoxt = (import ../development/compilers/strategoxt) {
+  inherit fetchurl pkgconfig sdf aterm;
+  stdenv = overrideInStdenv stdenv [gnumake380];
+};
+
+gnumake380 = <replaceable>...</replaceable>;</programlisting>
+     Likewise, there are many packages that don’t compile with the default GCC (4.1.1), but that’s easily fixed:
+<programlisting>
+exult = import ../games/exult {
+  inherit fetchurl SDL SDL_mixer zlib libpng unzip;
+  stdenv = overrideGCC stdenv gcc34;
+};</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     It has also become much easier to experiment with changes to the <literal>stdenv</literal> setup script (which notably contains the generic builder). Since edits to <filename>pkgs/stdenv/generic/setup.sh</filename> trigger a rebuild of <emphasis>everything</emphasis>, this was formerly quite painful. But now <literal>stdenv</literal> contains a function to “regenerate” <literal>stdenv</literal> with a different setup script, allowing the use of a different setup script for specific packages:
+<programlisting>
+pkg = import <replaceable>...</replaceable> {
+  stdenv = stdenv.regenerate ./my-setup.sh;
+  <replaceable>...</replaceable>
+}</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Packages can now have a human-readable <emphasis>description</emphasis> field. Package descriptions are shown by <literal>nix-env -qa --description</literal>. In addition, they’re shown on the Nixpkgs release page. A description can be added to a package as follows:
+<programlisting>
+stdenv.mkDerivation {
+  name = "exult-1.2";
+  <replaceable>...</replaceable>
+  meta = {
+    description = "A reimplementation of the Ultima VII game engine";
+  };
+}</programlisting>
+     The <varname>meta</varname> attribute is not passed to the builder, so changes to the description do not trigger a rebuild. Additional <varname>meta</varname> attributes may be defined in the future (such as the URL of the package’s homepage, the license, etc.).
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   The following people contributed to this release: Andres Löh, Armijn Hemel, Christof Douma, Eelco Dolstra, Eelco Visser, Mart Kolthof, Martin Bravenboer, Merijn de Jonge, Rob Vermaas and Roy van den Broek.
+  </para>
+ </section>
+ <section xml:id="release-notes-0.9">
+  <title>Release 0.9 (January 31, 2006)</title>
+
+  <para>
+   There have been zillions of changes since the last release of Nixpkgs. Many packages have been added or updated. The following are some of the more notable changes:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Distribution files have been moved to <link
+  xlink:href="http://nixos.org/" />.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The C library on Linux, Glibc, has been updated to version 2.3.6.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The default compiler is now GCC 3.4.5. GCC 4.0.2 is also available.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The old, unofficial Xlibs has been replaced by the official modularised X11 distribution from X.org, i.e., X11R7.0. X11R7.0 consists of 287 (!) packages, all of which are in Nixpkgs though not all have been tested. It is now possible to build a working X server (previously we only had X client libraries). We use a fully Nixified X server on NixOS.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The Sun JDK 5 has been purified, i.e., it doesn’t require any non-Nix components such as <filename>/lib/ld-linux.so.2</filename>. This means that Java applications such as Eclipse and Azureus can run on NixOS.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Hardware-accelerated OpenGL support, used by games like Quake 3 (which is now built from source).
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Improved support for FreeBSD on x86.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Improved Haskell support; e.g., the GHC build is now pure.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Some support for cross-compilation: cross-compiling builds of GCC and Binutils, and cross-compiled builds of the C library uClibc.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Notable new packages:
+     <itemizedlist>
+      <listitem>
+       <para>
+        teTeX, including support for building LaTeX documents using Nix (with automatic dependency determination).
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Ruby.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        System-level packages to support NixOS, e.g. Grub, GNU <literal>parted</literal> and so on.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <literal>ecj</literal>, the Eclipse Compiler for Java, so we finally have a freely distributable compiler that supports Java 5.0.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <literal>php</literal>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        The GIMP.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Inkscape.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        GAIM.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <literal>kdelibs</literal>. This allows us to add KDE-based packages (such as <literal>kcachegrind</literal>).
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+  </itemizedlist>
+
+  <para>
+   The following people contributed to this release: Andres Löh, Armijn Hemel, Bogdan Dumitriu, Christof Douma, Eelco Dolstra, Eelco Visser, Mart Kolthof, Martin Bravenboer, Rob Vermaas and Roy van den Broek.
+  </para>
+ </section>
+ <section xml:id="release-notes-0.8">
+  <title>Release 0.8 (April 11, 2005)</title>
+
+  <para>
+   This release is mostly to remain synchronised with the changed hashing scheme in Nix 0.8.
+  </para>
+
+  <para>
+   Notable updates:
+   <itemizedlist>
+    <listitem>
+     <para>
+      Adobe Reader 7.0
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Various security updates (zlib 1.2.2, etc.)
+     </para>
+    </listitem>
+   </itemizedlist>
+  </para>
+ </section>
+ <section xml:id="release-notes-0.7">
+  <title>Release 0.7 (March 14, 2005)</title>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     The bootstrap process for the standard build environment on Linux (stdenv-linux) has been improved. It is no longer dependent in its initial bootstrap stages on the system Glibc, GCC, and other tools. Rather, Nixpkgs contains a statically linked bash and curl, and uses that to download other statically linked tools. These are then used to build a Glibc and dynamically linked versions of all other tools.
+    </para>
+    <para>
+     This change also makes the bootstrap process faster. For instance, GCC is built only once instead of three times.
+    </para>
+    <para>
+     (Contributed by Armijn Hemel.)
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Tarballs used by Nixpkgs are now obtained from the same server that hosts Nixpkgs (<link
+  xlink:href="http://catamaran.labs.cs.uu.nl/" />). This reduces the risk of packages being unbuildable due to moved or deleted files on various servers.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     There now is a generic mechanism for building Perl modules. See the various Perl modules defined in pkgs/system/all-packages-generic.nix.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Notable new packages:
+     <itemizedlist>
+      <listitem>
+       <para>
+        Qt 3
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        MySQL
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        MythTV
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Mono
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        MonoDevelop (alpha)
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Xine
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Notable updates:
+     <itemizedlist>
+      <listitem>
+       <para>
+        GCC 3.4.3
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Glibc 2.3.4
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        GTK 2.6
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+  </itemizedlist>
+ </section>
+</article>

third_party/nixpkgs/doc/shell.nix

@@ -0,0 +1,5 @@
+{ pkgs ? import ../. {} }:
+(import ./default.nix {}).overrideAttrs (x: {
+  buildInputs = x.buildInputs ++ [ pkgs.xmloscopy pkgs.ruby ];
+
+})

third_party/nixpkgs/doc/stdenv/cross-compilation.xml

@@ -0,0 +1,394 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="chap-cross">
+ <title>Cross-compilation</title>
+ <section xml:id="sec-cross-intro">
+  <title>Introduction</title>
+
+  <para>
+   "Cross-compilation" means compiling a program on one machine for another type of machine. For example, a typical use of cross-compilation is to compile programs for embedded devices. These devices often don't have the computing power and memory to compile their own programs. One might think that cross-compilation is a fairly niche concern. However, there are significant advantages to rigorously distinguishing between build-time and run-time environments! Significant, because the benefits apply even when one is developing and deploying on the same machine. Nixpkgs is increasingly adopting the opinion that packages should be written with cross-compilation in mind, and nixpkgs should evaluate in a similar way (by minimizing cross-compilation-specific special cases) whether or not one is cross-compiling.
+  </para>
+
+  <para>
+   This chapter will be organized in three parts. First, it will describe the basics of how to package software in a way that supports cross-compilation. Second, it will describe how to use Nixpkgs when cross-compiling. Third, it will describe the internal infrastructure supporting cross-compilation.
+  </para>
+ </section>
+<!--============================================================-->
+ <section xml:id="sec-cross-packaging">
+  <title>Packaging in a cross-friendly manner</title>
+
+  <section xml:id="ssec-cross-platform-parameters">
+   <title>Platform parameters</title>
+
+   <para>
+    Nixpkgs follows the <link
+     xlink:href="https://gcc.gnu.org/onlinedocs/gccint/Configure-Terms.html">conventions of GNU autoconf</link>. We distinguish between 3 types of platforms when building a derivation: <wordasword>build</wordasword>, <wordasword>host</wordasword>, and <wordasword>target</wordasword>. In summary, <wordasword>build</wordasword> is the platform on which a package is being built, <wordasword>host</wordasword> is the platform on which it will run. The third attribute, <wordasword>target</wordasword>, is relevant only for certain specific compilers and build tools.
+   </para>
+
+   <para>
+    In Nixpkgs, these three platforms are defined as attribute sets under the names <literal>buildPlatform</literal>, <literal>hostPlatform</literal>, and <literal>targetPlatform</literal>. They are always defined as attributes in the standard environment. That means one can access them like:
+<programlisting>{ stdenv, fooDep, barDep, .. }: ...stdenv.buildPlatform...</programlisting>
+    .
+   </para>
+
+   <variablelist>
+    <varlistentry>
+     <term>
+      <varname>buildPlatform</varname>
+     </term>
+     <listitem>
+      <para>
+       The "build platform" is the platform on which a package is built. Once someone has a built package, or pre-built binary package, the build platform should not matter and can be ignored.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>hostPlatform</varname>
+     </term>
+     <listitem>
+      <para>
+       The "host platform" is the platform on which a package will be run. This is the simplest platform to understand, but also the one with the worst name.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>targetPlatform</varname>
+     </term>
+     <listitem>
+      <para>
+       The "target platform" attribute is, unlike the other two attributes, not actually fundamental to the process of building software. Instead, it is only relevant for compatibility with building certain specific compilers and build tools. It can be safely ignored for all other packages.
+      </para>
+      <para>
+       The build process of certain compilers is written in such a way that the compiler resulting from a single build can itself only produce binaries for a single platform. The task of specifying this single "target platform" is thus pushed to build time of the compiler. The root cause of this is that the compiler (which will be run on the host) and the standard library/runtime (which will be run on the target) are built by a single build process.
+      </para>
+      <para>
+       There is no fundamental need to think about a single target ahead of time like this. If the tool supports modular or pluggable backends, both the need to specify the target at build time and the constraint of having only a single target disappear. An example of such a tool is LLVM.
+      </para>
+      <para>
+       Although the existence of a "target platfom" is arguably a historical mistake, it is a common one: examples of tools that suffer from it are GCC, Binutils, GHC and Autoconf. Nixpkgs tries to avoid sharing in the mistake where possible. Still, because the concept of a target platform is so ingrained, it is best to support it as is.
+      </para>
+     </listitem>
+    </varlistentry>
+   </variablelist>
+
+   <para>
+    The exact schema these fields follow is a bit ill-defined due to a long and convoluted evolution, but this is slowly being cleaned up. You can see examples of ones used in practice in <literal>lib.systems.examples</literal>; note how they are not all very consistent. For now, here are few fields can count on them containing:
+   </para>
+
+   <variablelist>
+    <varlistentry>
+     <term>
+      <varname>system</varname>
+     </term>
+     <listitem>
+      <para>
+       This is a two-component shorthand for the platform. Examples of this would be "x86_64-darwin" and "i686-linux"; see <literal>lib.systems.doubles</literal> for more. The first component corresponds to the CPU architecture of the platform and the second to the operating system of the platform (<literal>[cpu]-[os]</literal>). This format has built-in support in Nix, such as the <varname>builtins.currentSystem</varname> impure string.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>config</varname>
+     </term>
+     <listitem>
+      <para>
+       This is a 3- or 4- component shorthand for the platform. Examples of this would be <literal>x86_64-unknown-linux-gnu</literal> and <literal>aarch64-apple-darwin14</literal>. This is a standard format called the "LLVM target triple", as they are pioneered by LLVM. In the 4-part form, this corresponds to <literal>[cpu]-[vendor]-[os]-[abi]</literal>. This format is strictly more informative than the "Nix host double", as the previous format could analogously be termed. This needs a better name than <varname>config</varname>!
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>parsed</varname>
+     </term>
+     <listitem>
+      <para>
+       This is a Nix representation of a parsed LLVM target triple with white-listed components. This can be specified directly, or actually parsed from the <varname>config</varname>. See <literal>lib.systems.parse</literal> for the exact representation.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>libc</varname>
+     </term>
+     <listitem>
+      <para>
+       This is a string identifying the standard C library used. Valid identifiers include "glibc" for GNU libc, "libSystem" for Darwin's Libsystem, and "uclibc" for µClibc. It should probably be refactored to use the module system, like <varname>parse</varname>.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>is*</varname>
+     </term>
+     <listitem>
+      <para>
+       These predicates are defined in <literal>lib.systems.inspect</literal>, and slapped onto every platform. They are superior to the ones in <varname>stdenv</varname> as they force the user to be explicit about which platform they are inspecting. Please use these instead of those.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>platform</varname>
+     </term>
+     <listitem>
+      <para>
+       This is, quite frankly, a dumping ground of ad-hoc settings (it's an attribute set). See <literal>lib.systems.platforms</literal> for examples—there's hopefully one in there that will work verbatim for each platform that is working. Please help us triage these flags and give them better homes!
+      </para>
+     </listitem>
+    </varlistentry>
+   </variablelist>
+  </section>
+
+  <section xml:id="ssec-cross-dependency-categorization">
+   <title>Theory of dependency categorization</title>
+
+   <note>
+    <para>
+     This is a rather philosophical description that isn't very Nixpkgs-specific. For an overview of all the relevant attributes given to <varname>mkDerivation</varname>, see <xref
+     linkend="ssec-stdenv-dependencies"/>. For a description of how everything is implemented, see <xref linkend="ssec-cross-dependency-implementation" />.
+    </para>
+   </note>
+
+   <para>
+    In this section we explore the relationship between both runtime and build-time dependencies and the 3 Autoconf platforms.
+   </para>
+
+   <para>
+    A run time dependency between two packages requires that their host platforms match. This is directly implied by the meaning of "host platform" and "runtime dependency": The package dependency exists while both packages are running on a single host platform.
+   </para>
+
+   <para>
+    A build time dependency, however, has a shift in platforms between the depending package and the depended-on package. "build time dependency" means that to build the depending package we need to be able to run the depended-on's package. The depending package's build platform is therefore equal to the depended-on package's host platform.
+   </para>
+
+   <para>
+    If both the dependency and depending packages aren't compilers or other machine-code-producing tools, we're done. And indeed <varname>buildInputs</varname> and <varname>nativeBuildInputs</varname> have covered these simpler build-time and run-time (respectively) changes for many years. But if the dependency does produce machine code, we might need to worry about its target platform too. In principle, that target platform might be any of the depending package's build, host, or target platforms, but we prohibit dependencies from a "later" platform to an earlier platform to limit confusion because we've never seen a legitimate use for them.
+   </para>
+
+   <para>
+    Finally, if the depending package is a compiler or other machine-code-producing tool, it might need dependencies that run at "emit time". This is for compilers that (regrettably) insist on being built together with their source langauges' standard libraries. Assuming build != host != target, a run-time dependency of the standard library cannot be run at the compiler's build time or run time, but only at the run time of code emitted by the compiler.
+   </para>
+
+   <para>
+    Putting this all together, that means we have dependencies in the form "host → target", in at most the following six combinations:
+    <table>
+     <caption>Possible dependency types</caption>
+     <thead>
+      <tr>
+       <th>Dependency's host platform</th>
+       <th>Dependency's target platform</th>
+      </tr>
+     </thead>
+     <tbody>
+      <tr>
+       <td>build</td>
+       <td>build</td>
+      </tr>
+      <tr>
+       <td>build</td>
+       <td>host</td>
+      </tr>
+      <tr>
+       <td>build</td>
+       <td>target</td>
+      </tr>
+      <tr>
+       <td>host</td>
+       <td>host</td>
+      </tr>
+      <tr>
+       <td>host</td>
+       <td>target</td>
+      </tr>
+      <tr>
+       <td>target</td>
+       <td>target</td>
+      </tr>
+     </tbody>
+    </table>
+   </para>
+
+   <para>
+    Some examples will make this table clearer. Suppose there's some package that is being built with a <literal>(build, host, target)</literal> platform triple of <literal>(foo, bar, baz)</literal>. If it has a build-time library dependency, that would be a "host → build" dependency with a triple of <literal>(foo, foo, *)</literal> (the target platform is irrelevant). If it needs a compiler to be built, that would be a "build → host" dependency with a triple of <literal>(foo, foo, *)</literal> (the target platform is irrelevant). That compiler, would be built with another compiler, also "build → host" dependency, with a triple of <literal>(foo, foo, foo)</literal>.
+   </para>
+  </section>
+
+  <section xml:id="ssec-cross-cookbook">
+   <title>Cross packaging cookbook</title>
+
+   <para>
+    Some frequently encountered problems when packaging for cross-compilation should be answered here. Ideally, the information above is exhaustive, so this section cannot provide any new information, but it is ludicrous and cruel to expect everyone to spend effort working through the interaction of many features just to figure out the same answer to the same common problem. Feel free to add to this list!
+   </para>
+
+   <qandaset>
+    <qandaentry xml:id="cross-qa-build-c-program-in-build-environment">
+     <question>
+      <para>
+       What if my package's build system needs to build a C program to be run under the build environment?
+      </para>
+     </question>
+     <answer>
+      <para>
+<programlisting>depsBuildBuild = [ buildPackages.stdenv.cc ];</programlisting>
+       Add it to your <function>mkDerivation</function> invocation.
+      </para>
+     </answer>
+    </qandaentry>
+    <qandaentry xml:id="cross-qa-fails-to-find-ar">
+     <question>
+      <para>
+       My package fails to find <command>ar</command>.
+      </para>
+     </question>
+     <answer>
+      <para>
+       Many packages assume that an unprefixed <command>ar</command> is available, but Nix doesn't provide one. It only provides a prefixed one, just as it only does for all the other binutils programs. It may be necessary to patch the package to fix the build system to use a prefixed <command>ar</command>.
+      </para>
+     </answer>
+    </qandaentry>
+    <qandaentry xml:id="cross-testsuite-runs-host-code">
+     <question>
+      <para>
+       My package's testsuite needs to run host platform code.
+      </para>
+     </question>
+     <answer>
+      <para>
+<programlisting>doCheck = stdenv.hostPlatform == stdenv.buildPlatfrom;</programlisting>
+       Add it to your <function>mkDerivation</function> invocation.
+      </para>
+     </answer>
+    </qandaentry>
+   </qandaset>
+  </section>
+ </section>
+<!--============================================================-->
+ <section xml:id="sec-cross-usage">
+  <title>Cross-building packages</title>
+
+  <para>
+   Nixpkgs can be instantiated with <varname>localSystem</varname> alone, in which case there is no cross-compiling and everything is built by and for that system, or also with <varname>crossSystem</varname>, in which case packages run on the latter, but all building happens on the former. Both parameters take the same schema as the 3 (build, host, and target) platforms defined in the previous section. As mentioned above, <literal>lib.systems.examples</literal> has some platforms which are used as arguments for these parameters in practice. You can use them programmatically, or on the command line:
+<programlisting>
+nix-build '&lt;nixpkgs&gt;' --arg crossSystem '(import &lt;nixpkgs/lib&gt;).systems.examples.fooBarBaz' -A whatever</programlisting>
+  </para>
+
+  <note>
+   <para>
+    Eventually we would like to make these platform examples an unnecessary convenience so that
+<programlisting>
+nix-build '&lt;nixpkgs&gt;' --arg crossSystem '{ config = "&lt;arch&gt;-&lt;os&gt;-&lt;vendor&gt;-&lt;abi&gt;"; }' -A whatever</programlisting>
+    works in the vast majority of cases. The problem today is dependencies on other sorts of configuration which aren't given proper defaults. We rely on the examples to crudely to set those configuration parameters in some vaguely sane manner on the users behalf. Issue <link xlink:href="https://github.com/NixOS/nixpkgs/issues/34274">#34274</link> tracks this inconvenience along with its root cause in crufty configuration options.
+   </para>
+  </note>
+
+  <para>
+   While one is free to pass both parameters in full, there's a lot of logic to fill in missing fields. As discussed in the previous section, only one of <varname>system</varname>, <varname>config</varname>, and <varname>parsed</varname> is needed to infer the other two. Additionally, <varname>libc</varname> will be inferred from <varname>parse</varname>. Finally, <literal>localSystem.system</literal> is also <emphasis>impurely</emphasis> inferred based on the platform evaluation occurs. This means it is often not necessary to pass <varname>localSystem</varname> at all, as in the command-line example in the previous paragraph.
+  </para>
+
+  <note>
+   <para>
+    Many sources (manual, wiki, etc) probably mention passing <varname>system</varname>, <varname>platform</varname>, along with the optional <varname>crossSystem</varname> to nixpkgs: <literal>import &lt;nixpkgs&gt; { system = ..; platform = ..; crossSystem = ..; }</literal>. Passing those two instead of <varname>localSystem</varname> is still supported for compatibility, but is discouraged. Indeed, much of the inference we do for these parameters is motivated by compatibility as much as convenience.
+   </para>
+  </note>
+
+  <para>
+   One would think that <varname>localSystem</varname> and <varname>crossSystem</varname> overlap horribly with the three <varname>*Platforms</varname> (<varname>buildPlatform</varname>, <varname>hostPlatform,</varname> and <varname>targetPlatform</varname>; see <varname>stage.nix</varname> or the manual). Actually, those identifiers are purposefully not used here to draw a subtle but important distinction: While the granularity of having 3 platforms is necessary to properly *build* packages, it is overkill for specifying the user's *intent* when making a build plan or package set. A simple "build vs deploy" dichotomy is adequate: the sliding window principle described in the previous section shows how to interpolate between the these two "end points" to get the 3 platform triple for each bootstrapping stage. That means for any package a given package set, even those not bound on the top level but only reachable via dependencies or <varname>buildPackages</varname>, the three platforms will be defined as one of <varname>localSystem</varname> or <varname>crossSystem</varname>, with the former replacing the latter as one traverses build-time dependencies. A last simple difference is that <varname>crossSystem</varname> should be null when one doesn't want to cross-compile, while the <varname>*Platform</varname>s are always non-null. <varname>localSystem</varname> is always non-null.
+  </para>
+ </section>
+<!--============================================================-->
+ <section xml:id="sec-cross-infra">
+  <title>Cross-compilation infrastructure</title>
+
+  <section xml:id="ssec-cross-dependency-implementation">
+   <title>Implementation of dependencies</title>
+
+   <para>
+    The categorizes of dependencies developed in <xref
+    linkend="ssec-cross-dependency-categorization"/> are specified as lists of derivations given to <varname>mkDerivation</varname>, as documented in <xref linkend="ssec-stdenv-dependencies"/>. In short, each list of dependencies for "host → target" of "foo → bar" is called <varname>depsFooBar</varname>, with exceptions for backwards compatibility that <varname>depsBuildHost</varname> is instead called <varname>nativeBuildInputs</varname> and <varname>depsHostTarget</varname> is instead called <varname>buildInputs</varname>. Nixpkgs is now structured so that each <varname>depsFooBar</varname> is automatically taken from <varname>pkgsFooBar</varname>. (These <varname>pkgsFooBar</varname>s are quite new, so there is no special case for <varname>nativeBuildInputs</varname> and <varname>buildInputs</varname>.) For example, <varname>pkgsBuildHost.gcc</varname> should be used at build-time, while <varname>pkgsHostTarget.gcc</varname> should be used at run-time.
+   </para>
+
+   <para>
+    Now, for most of Nixpkgs's history, there were no <varname>pkgsFooBar</varname> attributes, and most packages have not been refactored to use it explicitly. Prior to those, there were just <varname>buildPackages</varname>, <varname>pkgs</varname>, and <varname>targetPackages</varname>. Those are now redefined as aliases to <varname>pkgsBuildHost</varname>, <varname>pkgsHostTarget</varname>, and <varname>pkgsTargetTarget</varname>. It is acceptable, even recommended, to use them for libraries to show that the host platform is irrelevant.
+   </para>
+
+   <para>
+    But before that, there was just <varname>pkgs</varname>, even though both <varname>buildInputs</varname> and <varname>nativeBuildInputs</varname> existed. [Cross barely worked, and those were implemented with some hacks on <varname>mkDerivation</varname> to override dependencies.] What this means is the vast majority of packages do not use any explicit package set to populate their dependencies, just using whatever <varname>callPackage</varname> gives them even if they do correctly sort their dependencies into the multiple lists described above. And indeed, asking that users both sort their dependencies, <emphasis>and</emphasis> take them from the right attribute set, is both too onerous and redundant, so the recommended approach (for now) is to continue just categorizing by list and not using an explicit package set.
+   </para>
+
+   <para>
+    To make this work, we "splice" together the six <varname>pkgsFooBar</varname> package sets and have <varname>callPackage</varname> actually take its arguments from that. This is currently implemented in <filename>pkgs/top-level/splice.nix</filename>. <varname>mkDerivation</varname> then, for each dependency attribute, pulls the right derivation out from the splice. This splicing can be skipped when not cross-compiling as the package sets are the same, but still is a bit slow for cross-compiling. We'd like to do something better, but haven't come up with anything yet.
+   </para>
+  </section>
+
+  <section xml:id="ssec-bootstrapping">
+   <title>Bootstrapping</title>
+
+   <para>
+    Each of the package sets described above come from a single bootstrapping stage. While <filename>pkgs/top-level/default.nix</filename>, coordinates the composition of stages at a high level, <filename>pkgs/top-level/stage.nix</filename> "ties the knot" (creates the fixed point) of each stage. The package sets are defined per-stage however, so they can be thought of as edges between stages (the nodes) in a graph. Compositions like <literal>pkgsBuildTarget.targetPackages</literal> can be thought of as paths to this graph.
+   </para>
+
+   <para>
+    While there are many package sets, and thus many edges, the stages can also be arranged in a linear chain. In other words, many of the edges are redundant as far as connectivity is concerned. This hinges on the type of bootstrapping we do. Currently for cross it is:
+    <orderedlist>
+     <listitem>
+      <para>
+       <literal>(native, native, native)</literal>
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       <literal>(native, native, foreign)</literal>
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       <literal>(native, foreign, foreign)</literal>
+      </para>
+     </listitem>
+    </orderedlist>
+    In each stage, <varname>pkgsBuildHost</varname> refers to the previous stage, <varname>pkgsBuildBuild</varname> refers to the one before that, and <varname>pkgsHostTarget</varname> refers to the current one, and <varname>pkgsTargetTarget</varname> refers to the next one. When there is no previous or next stage, they instead refer to the current stage. Note how all the invariants regarding the mapping between dependency and depending packages' build host and target platforms are preserved. <varname>pkgsBuildTarget</varname> and <varname>pkgsHostHost</varname> are more complex in that the stage fitting the requirements isn't always a fixed chain of "prevs" and "nexts" away (modulo the "saturating" self-references at the ends). We just special case each instead. All the primary edges are implemented is in <filename>pkgs/stdenv/booter.nix</filename>, and secondarily aliases in <filename>pkgs/top-level/stage.nix</filename>.
+   </para>
+
+   <note>
+    <para>
+     Note the native stages are bootstrapped in legacy ways that predate the current cross implementation. This is why the bootstrapping stages leading up to the final stages are ignored inthe previous paragraph.
+    </para>
+   </note>
+
+   <para>
+    If one looks at the 3 platform triples, one can see that they overlap such that one could put them together into a chain like:
+<programlisting>
+(native, native, native, foreign, foreign)
+</programlisting>
+    If one imagines the saturating self references at the end being replaced with infinite stages, and then overlays those platform triples, one ends up with the infinite tuple:
+<programlisting>
+(native..., native, native, native, foreign, foreign, foreign...)
+</programlisting>
+    On can then imagine any sequence of platforms such that there are bootstrap stages with their 3 platforms determined by "sliding a window" that is the 3 tuple through the sequence. This was the original model for bootstrapping. Without a target platform (assume a better world where all compilers are multi-target and all standard libraries are built in their own derivation), this is sufficient. Conversely if one wishes to cross compile "faster", with a "Canadian Cross" bootstraping stage where <literal>build != host != target</literal>, more bootstrapping stages are needed since no sliding window providess the pesky <varname>pkgsBuildTarget</varname> package set since it skips the Canadian cross stage's "host".
+   </para>
+
+   <note>
+    <para>
+     It is much better to refer to <varname>buildPackages</varname> than <varname>targetPackages</varname>, or more broadly package sets that do not mention "target". There are three reasons for this.
+    </para>
+    <para>
+     First, it is because bootstrapping stages do not have a unique <varname>targetPackages</varname>. For example a <literal>(x86-linux, x86-linux, arm-linux)</literal> and <literal>(x86-linux, x86-linux, x86-windows)</literal> package set both have a <literal>(x86-linux, x86-linux, x86-linux)</literal> package set. Because there is no canonical <varname>targetPackages</varname> for such a native (<literal>build == host == target</literal>) package set, we set their <varname>targetPackages</varname>
+    </para>
+    <para>
+     Second, it is because this is a frequent source of hard-to-follow "infinite recursions" / cycles. When only package sets that don't mention target are used, the package set forms a directed acyclic graph. This means that all cycles that exist are confined to one stage. This means they are a lot smaller, and easier to follow in the code or a backtrace. It also means they are present in native and cross builds alike, and so more likely to be caught by CI and other users.
+    </para>
+    <para>
+     Thirdly, it is because everything target-mentioning only exists to accommodate compilers with lousy build systems that insist on the compiler itself and standard library being built together. Of course that is bad because bigger derivations means longer rebuilds. It is also problematic because it tends to make the standard libraries less like other libraries than they could be, complicating code and build systems alike. Because of the other problems, and because of these innate disadvantages, compilers ought to be packaged another way where possible.
+    </para>
+   </note>
+
+   <note>
+    <para>
+     If one explores Nixpkgs, they will see derivations with names like <literal>gccCross</literal>. Such <literal>*Cross</literal> derivations is a holdover from before we properly distinguished between the host and target platforms—the derivation with "Cross" in the name covered the <literal>build = host != target</literal> case, while the other covered the <literal>host = target</literal>, with build platform the same or not based on whether one was using its <literal>.nativeDrv</literal> or <literal>.crossDrv</literal>. This ugliness will disappear soon.
+    </para>
+   </note>
+  </section>
+ </section>
+</chapter>

third_party/nixpkgs/doc/stdenv/meta.xml

@@ -0,0 +1,350 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="chap-meta">
+ <title>Meta-attributes</title>
+ <para>
+  Nix packages can declare <emphasis>meta-attributes</emphasis> that contain information about a package such as a description, its homepage, its license, and so on. For instance, the GNU Hello package has a <varname>meta</varname> declaration like this:
+<programlisting>
+meta = with stdenv.lib; {
+  description = "A program that produces a familiar, friendly greeting";
+  longDescription = ''
+    GNU Hello is a program that prints "Hello, world!" when you run it.
+    It is fully customizable.
+  '';
+  homepage = "https://www.gnu.org/software/hello/manual/";
+  license = licenses.gpl3Plus;
+  maintainers = [ maintainers.eelco ];
+  platforms = platforms.all;
+};
+</programlisting>
+ </para>
+ <para>
+  Meta-attributes are not passed to the builder of the package. Thus, a change to a meta-attribute doesn’t trigger a recompilation of the package. The value of a meta-attribute must be a string.
+ </para>
+ <para>
+  The meta-attributes of a package can be queried from the command-line using <command>nix-env</command>:
+<screen>
+<prompt>$ </prompt>nix-env -qa hello --json
+{
+    "hello": {
+        "meta": {
+            "description": "A program that produces a familiar, friendly greeting",
+            "homepage": "https://www.gnu.org/software/hello/manual/",
+            "license": {
+                "fullName": "GNU General Public License version 3 or later",
+                "shortName": "GPLv3+",
+                "url": "http://www.fsf.org/licensing/licenses/gpl.html"
+            },
+            "longDescription": "GNU Hello is a program that prints \"Hello, world!\" when you run it.\nIt is fully customizable.\n",
+            "maintainers": [
+                "Ludovic Court\u00e8s &lt;ludo@gnu.org>"
+            ],
+            "platforms": [
+                "i686-linux",
+                "x86_64-linux",
+                "armv5tel-linux",
+                "armv7l-linux",
+                "mips32-linux",
+                "x86_64-darwin",
+                "i686-cygwin",
+                "i686-freebsd",
+                "x86_64-freebsd",
+                "i686-openbsd",
+                "x86_64-openbsd"
+            ],
+            "position": "/home/user/dev/nixpkgs/pkgs/applications/misc/hello/default.nix:14"
+        },
+        "name": "hello-2.9",
+        "system": "x86_64-linux"
+    }
+}
+
+
+</screen>
+  <command>nix-env</command> knows about the <varname>description</varname> field specifically:
+<screen>
+<prompt>$ </prompt>nix-env -qa hello --description
+hello-2.3  A program that produces a familiar, friendly greeting
+</screen>
+ </para>
+ <section xml:id="sec-standard-meta-attributes">
+  <title>Standard meta-attributes</title>
+
+  <para>
+   It is expected that each meta-attribute is one of the following:
+  </para>
+
+  <variablelist>
+   <varlistentry>
+    <term>
+     <varname>description</varname>
+    </term>
+    <listitem>
+     <para>
+      A short (one-line) description of the package. This is shown by <command>nix-env -q --description</command> and also on the Nixpkgs release pages.
+     </para>
+     <para>
+      Don’t include a period at the end. Don’t include newline characters. Capitalise the first character. For brevity, don’t repeat the name of package — just describe what it does.
+     </para>
+     <para>
+      Wrong: <literal>"libpng is a library that allows you to decode PNG images."</literal>
+     </para>
+     <para>
+      Right: <literal>"A library for decoding PNG images"</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>longDescription</varname>
+    </term>
+    <listitem>
+     <para>
+      An arbitrarily long description of the package.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>branch</varname>
+    </term>
+    <listitem>
+     <para>
+      Release branch. Used to specify that a package is not going to receive updates that are not in this branch; for example, Linux kernel 3.0 is supposed to be updated to 3.0.X, not 3.1.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>homepage</varname>
+    </term>
+    <listitem>
+     <para>
+      The package’s homepage. Example: <literal>https://www.gnu.org/software/hello/manual/</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>downloadPage</varname>
+    </term>
+    <listitem>
+     <para>
+      The page where a link to the current version can be found. Example: <literal>https://ftp.gnu.org/gnu/hello/</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>changelog</varname>
+    </term>
+    <listitem>
+     <para>
+      A link or a list of links to the location of Changelog for a package. A link may use expansion to refer to the correct changelog version. Example: <literal>"https://git.savannah.gnu.org/cgit/hello.git/plain/NEWS?h=v${version}"</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>license</varname>
+    </term>
+    <listitem>
+     <para>
+      The license, or licenses, for the package. One from the attribute set defined in <link
+          xlink:href="https://github.com/NixOS/nixpkgs/blob/master/lib/licenses.nix"> <filename>nixpkgs/lib/licenses.nix</filename></link>. At this moment using both a list of licenses and a single license is valid. If the license field is in the form of a list representation, then it means that parts of the package are licensed differently. Each license should preferably be referenced by their attribute. The non-list attribute value can also be a space delimited string representation of the contained attribute shortNames or spdxIds. The following are all valid examples:
+      <itemizedlist>
+       <listitem>
+        <para>
+         Single license referenced by attribute (preferred) <literal>stdenv.lib.licenses.gpl3</literal>.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Single license referenced by its attribute shortName (frowned upon) <literal>"gpl3"</literal>.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Single license referenced by its attribute spdxId (frowned upon) <literal>"GPL-3.0"</literal>.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Multiple licenses referenced by attribute (preferred) <literal>with stdenv.lib.licenses; [ asl20 free ofl ]</literal>.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Multiple licenses referenced as a space delimited string of attribute shortNames (frowned upon) <literal>"asl20 free ofl"</literal>.
+        </para>
+       </listitem>
+      </itemizedlist>
+      For details, see <xref linkend='sec-meta-license'/>.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>maintainers</varname>
+    </term>
+    <listitem>
+     <para>
+      A list of names and e-mail addresses of the maintainers of this Nix expression. If you would like to be a maintainer of a package, you may want to add yourself to <link
+    xlink:href="https://github.com/NixOS/nixpkgs/blob/master/maintainers/maintainer-list.nix"><filename>nixpkgs/maintainers/maintainer-list.nix</filename></link> and write something like <literal>[ stdenv.lib.maintainers.alice stdenv.lib.maintainers.bob ]</literal>.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>priority</varname>
+    </term>
+    <listitem>
+     <para>
+      The <emphasis>priority</emphasis> of the package, used by <command>nix-env</command> to resolve file name conflicts between packages. See the Nix manual page for <command>nix-env</command> for details. Example: <literal>"10"</literal> (a low-priority package).
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>platforms</varname>
+    </term>
+    <listitem>
+     <para>
+      The list of Nix platform types on which the package is supported. Hydra builds packages according to the platform specified. If no platform is specified, the package does not have prebuilt binaries. An example is:
+<programlisting>
+meta.platforms = stdenv.lib.platforms.linux;
+</programlisting>
+      Attribute Set <varname>stdenv.lib.platforms</varname> defines <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/lib/systems/doubles.nix"> various common lists</link> of platforms types.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>tests</varname>
+    </term>
+    <listitem>
+     <warning>
+      <para>
+       This attribute is special in that it is not actually under the <literal>meta</literal> attribute set but rather under the <literal>passthru</literal> attribute set. This is due to how <literal>meta</literal> attributes work, and the fact that they are supposed to contain only metadata, not derivations.
+      </para>
+     </warning>
+     <para>
+      An attribute set with as values tests. A test is a derivation, which builds successfully when the test passes, and fails to build otherwise. A derivation that is a test needs to have <literal>meta.timeout</literal> defined.
+     </para>
+     <para>
+      The NixOS tests are available as <literal>nixosTests</literal> in parameters of derivations. For instance, the OpenSMTPD derivation includes lines similar to:
+<programlisting>
+{ /* ... */, nixosTests }:
+{
+  # ...
+  passthru.tests = {
+    basic-functionality-and-dovecot-integration = nixosTests.opensmtpd;
+  };
+}
+</programlisting>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>timeout</varname>
+    </term>
+    <listitem>
+     <para>
+      A timeout (in seconds) for building the derivation. If the derivation takes longer than this time to build, it can fail due to breaking the timeout. However, all computers do not have the same computing power, hence some builders may decide to apply a multiplicative factor to this value. When filling this value in, try to keep it approximately consistent with other values already present in <literal>nixpkgs</literal>.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>hydraPlatforms</varname>
+    </term>
+    <listitem>
+     <para>
+      The list of Nix platform types for which the Hydra instance at <literal>hydra.nixos.org</literal> will build the package. (Hydra is the Nix-based continuous build system.) It defaults to the value of <varname>meta.platforms</varname>. Thus, the only reason to set <varname>meta.hydraPlatforms</varname> is if you want <literal>hydra.nixos.org</literal> to build the package on a subset of <varname>meta.platforms</varname>, or not at all, e.g.
+<programlisting>
+meta.platforms = stdenv.lib.platforms.linux;
+meta.hydraPlatforms = [];
+</programlisting>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>broken</varname>
+    </term>
+    <listitem>
+     <para>
+      If set to <literal>true</literal>, the package is marked as “broken”, meaning that it won’t show up in <literal>nix-env -qa</literal>, and cannot be built or installed. Such packages should be removed from Nixpkgs eventually unless they are fixed.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>updateWalker</varname>
+    </term>
+    <listitem>
+     <para>
+      If set to <literal>true</literal>, the package is tested to be updated correctly by the <literal>update-walker.sh</literal> script without additional settings. Such packages have <varname>meta.version</varname> set and their homepage (or the page specified by <varname>meta.downloadPage</varname>) contains a direct link to the package tarball.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+ </section>
+ <section xml:id="sec-meta-license">
+  <title>Licenses</title>
+
+  <para>
+   The <varname>meta.license</varname> attribute should preferrably contain a value from <varname>stdenv.lib.licenses</varname> defined in <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/lib/licenses.nix"> <filename>nixpkgs/lib/licenses.nix</filename></link>, or in-place license description of the same format if the license is unlikely to be useful in another expression.
+  </para>
+
+  <para>
+   Although it's typically better to indicate the specific license, a few generic options are available:
+   <variablelist>
+    <varlistentry>
+     <term>
+      <varname>stdenv.lib.licenses.free</varname>, <varname>"free"</varname>
+     </term>
+     <listitem>
+      <para>
+       Catch-all for free software licenses not listed above.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>stdenv.lib.licenses.unfreeRedistributable</varname>, <varname>"unfree-redistributable"</varname>
+     </term>
+     <listitem>
+      <para>
+       Unfree package that can be redistributed in binary form. That is, it’s legal to redistribute the <emphasis>output</emphasis> of the derivation. This means that the package can be included in the Nixpkgs channel.
+      </para>
+      <para>
+       Sometimes proprietary software can only be redistributed unmodified. Make sure the builder doesn’t actually modify the original binaries; otherwise we’re breaking the license. For instance, the NVIDIA X11 drivers can be redistributed unmodified, but our builder applies <command>patchelf</command> to make them work. Thus, its license is <varname>"unfree"</varname> and it cannot be included in the Nixpkgs channel.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>stdenv.lib.licenses.unfree</varname>, <varname>"unfree"</varname>
+     </term>
+     <listitem>
+      <para>
+       Unfree package that cannot be redistributed. You can build it yourself, but you cannot redistribute the output of the derivation. Thus it cannot be included in the Nixpkgs channel.
+      </para>
+     </listitem>
+    </varlistentry>
+    <varlistentry>
+     <term>
+      <varname>stdenv.lib.licenses.unfreeRedistributableFirmware</varname>, <varname>"unfree-redistributable-firmware"</varname>
+     </term>
+     <listitem>
+      <para>
+       This package supplies unfree, redistributable firmware. This is a separate value from <varname>unfree-redistributable</varname> because not everybody cares whether firmware is free.
+      </para>
+     </listitem>
+    </varlistentry>
+   </variablelist>
+  </para>
+ </section>
+</chapter>