libGLU: Add `meta.pkgConfigModules` and test

pkgs/development/libraries/mesa-glu/default.nix

···
-{ lib, stdenv, fetchurl, pkg-config, libGL, ApplicationServices }:
+{ lib, stdenv, fetchurl, pkg-config, libGL, ApplicationServices
+, testers
+}:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation (finalAttrs: {
   pname = "glu";
   version = "9.0.2";
 
-  src = fetchurl {
+  src = let
+    inherit (finalAttrs) pname version;
+  in fetchurl {
     url = "https://mesa.freedesktop.org/archive/${pname}/${pname}-${version}.tar.xz";
     sha256 = "sha256-bnKA/1hcah2d/N8vykiSUWNLM3e/wzwp5AAkZqONAtQ=";
   };
···
     ++ lib.optional stdenv.isDarwin ApplicationServices;
 
   outputs = [ "out" "dev" ];
+
+  passthru.tests.pkg-config = testers.testMetaPkgConfig finalAttrs.finalPackage;
 
   meta = {
     description = "OpenGL utility library";
     homepage = "https://cgit.freedesktop.org/mesa/glu/";
     license = lib.licenses.sgi-b-20;
+    pkgConfigModules = [ "glu" ];
     platforms = lib.platforms.unix;
     broken = stdenv.hostPlatform.isAndroid;
   };
-}
+})