commit b273c9f7ab10475787db4d6e09bd4b71b374d0ec
Author: sternenseemann <0rpkxez4ksa01gb3typccl0i@systemli.org>
Date:   Thu Mar 18 01:28:46 2021 +0100

    Let user specify solo5-binding to use
    
    This is a little feature for the configure script I wanted to have for
    the NixOS package: It allows the user to set PKG_CONFIG_DEPS before
    running configure.sh to disable the autodetection mechanism. This is
    useful for NixOS as we have all bindings bundled in the solo5 package,
    so the result would also be solo5-bindings-xen. Additionally, it allows
    us to do the binding selection declaratively and minimize the risk of
    accidentally switching backend.
    
    PKG_CONFIG_DEPS seems like a bit of an unappropriate variable name for a
    user “interface”, let me know if you want a dedicated environment
    variable for this in case there will be more PKG_CONFIG_DEPS.

diff --git a/configure.sh b/configure.sh
index c254f7b..c675a02 100755
--- a/configure.sh
+++ b/configure.sh
@@ -11,13 +11,19 @@ if pkg_exists solo5-bindings-hvt solo5-bindings-spt solo5-bindings-virtio solo5-
     echo "ERROR: Only one of solo5-bindings-hvt, solo5-bindings-spt, solo5-bindings-virtio, solo5-bindings-muen, solo5-bindings-genode, solo5-bindings-xen can be installed." 1>&2
     exit 1
 fi
-PKG_CONFIG_DEPS=
-pkg_exists solo5-bindings-hvt && PKG_CONFIG_DEPS=solo5-bindings-hvt
-pkg_exists solo5-bindings-spt && PKG_CONFIG_DEPS=solo5-bindings-spt
-pkg_exists solo5-bindings-muen && PKG_CONFIG_DEPS=solo5-bindings-muen
-pkg_exists solo5-bindings-virtio && PKG_CONFIG_DEPS=solo5-bindings-virtio
-pkg_exists solo5-bindings-genode && PKG_CONFIG_DEPS=solo5-bindings-genode
-pkg_exists solo5-bindings-xen && PKG_CONFIG_DEPS=solo5-bindings-xen
+if [ -z "${PKG_CONFIG_DEPS}" ]; then
+    PKG_CONFIG_DEPS=
+    pkg_exists solo5-bindings-hvt && PKG_CONFIG_DEPS=solo5-bindings-hvt
+    pkg_exists solo5-bindings-spt && PKG_CONFIG_DEPS=solo5-bindings-spt
+    pkg_exists solo5-bindings-muen && PKG_CONFIG_DEPS=solo5-bindings-muen
+    pkg_exists solo5-bindings-virtio && PKG_CONFIG_DEPS=solo5-bindings-virtio
+    pkg_exists solo5-bindings-genode && PKG_CONFIG_DEPS=solo5-bindings-genode
+    pkg_exists solo5-bindings-xen && PKG_CONFIG_DEPS=solo5-bindings-xen
+else
+    pkg_exists "${PKG_CONFIG_DEPS}" \
+        || (echo "ERROR: ${PKG_CONFIG_DEPS} is not installed" 1>&2; exit 1) \
+        || exit 1
+fi
 if [ -z "${PKG_CONFIG_DEPS}" ]; then
     echo "ERROR: No supported Solo5 bindings package found." 1>&2
     echo "ERROR: solo5-bindings-hvt, solo5-bindings-spt, solo5-bindings-virtio, solo5-bindings-muen, solo5-bindings-genode or solo5-bindings-xen must be installed." 1>&2