diff -Naur postgresql-9.6.1-orig/src/common/config_info.c postgresql-9.6.1/src/common/config_info.c
--- postgresql-9.6.1-orig/src/common/config_info.c	2016-11-22 21:39:29.231929261 +0100
+++ postgresql-9.6.1/src/common/config_info.c	2016-11-22 23:36:53.685163543 +0100
@@ -118,7 +118,10 @@
 	i++;

 	configdata[i].name = pstrdup("PGXS");
+	strlcpy(path, "HARDCODED_PGXS_PATH", sizeof(path));
+/* commented out to be able to point to nix $out path
 	get_pkglib_path(my_exec_path, path);
+*/
 	strlcat(path, "/pgxs/src/makefiles/pgxs.mk", sizeof(path));
 	cleanup_path(path);
 	configdata[i].setting = pstrdup(path);