dri-pkgconfig-stub: init

This is a tiny stub that can be provided to things that just
want to know where to find DRI drivers for whatever reason
(looking at you, Chromium), so they don't have to pull in all
of Mesa.

pkgs/by-name/dr/dri-pkgconfig-stub/package.nix

@@ -0,0 +1,20 @@
+{
+  lib,
+  writeTextFile,
+  mesa,
+}:
+writeTextFile {
+  name = "dri-pkgconfig-stub";
+
+  text = ''
+    dridriverdir=${mesa.driverLink}/lib/dri
+
+    Name: dri
+    Version: ${mesa.version}
+    Description: Nixpkgs graphics driver path stub
+  '';
+
+  destination = "/lib/pkgconfig/dri.pc";
+
+  meta.badPlatforms = lib.platforms.darwin;
+}