Allow overriding package variables with env vars

pkg-config allows a way to override package variables through the
--define-prefix interface, but this is very cumbersome to do in a global
way since it always needs to be passed on the command line and the
override cannot be scoped to a single packge.

Allow overriding package variables using environment variables of the
form PKG_CONFIG_$PACKAGE_$VARIABLE. For example, setting
PKG_CONFIG_GLADEUI_2_0_CATALOGDIR will override the variable
"catalogdir" in the "gladeui-2.0" package.

https://bugs.freedesktop.org/show_bug.cgi?id=90917

2 files changed, 38 insertions, 1 deletions

diff --git a/check/Makefile.am b/check/Makefile.am
index 34d0e34..4f92e0d 100644
--- a/check/Makefile.am
+++ b/check/Makefile.am
@@ -26,7 +26,9 @@ TESTS = \
 	check-debug \
 	check-gtk \
 	check-tilde \
-	check-relocatable
+	check-relocatable \
+	check-variable-override \
+	$(NULL)
 
 EXTRA_DIST = \
 	$(TESTS) \
diff --git a/check/check-variable-override b/check/check-variable-override
new file mode 100755
index 0000000..e3f6cbd
--- /dev/null
+++ b/check/check-variable-override
@@ -0,0 +1,35 @@
+#! /bin/sh
+
+set -e
+
+. ${srcdir}/common
+
+# Check the normal behavior
+RESULT="/usr"
+run_test --variable=prefix simple
+RESULT="/usr/lib"
+run_test --variable=libdir simple
+
+# Override prefix with correct environment variable
+export PKG_CONFIG_SIMPLE_PREFIX="/foo"
+RESULT="/foo"
+run_test --variable=prefix simple
+RESULT="/foo/lib"
+run_test --variable=libdir simple
+RESULT="-I/foo/include"
+run_test --cflags simple
+unset PKG_CONFIG_SIMPLE_PREFIX
+
+# Override prefix with incorrect environment variable case. On Windows
+# this will have no effect as environment variables are case
+# insensitive.
+if [ "$native_win32" != yes ]; then
+    export PKG_CONFIG_SIMPLE_prefix="/foo"
+    RESULT="/usr"
+    run_test --variable=prefix simple
+    RESULT="/usr/lib"
+    run_test --variable=libdir simple
+    RESULT=""
+    run_test --cflags simple
+    unset PKG_CONFIG_SIMPLE_prefix
+fi