KDE4: fix sound using the old gstreamer approach; the correct way would be to wrap each and every phonon client, or patch phonon's search path

nixos/modules/services/x11/desktop-managers/kde4.nix

@@ -161,6 +161,10 @@ in
 
     environment.pathsToLink = [ "/share" ];
 
+    environment.profileRelativeEnvVars = mkIf (lib.elem "gstreamer" cfg.phononBackends) {
+      GST_PLUGIN_SYSTEM_PATH = [ "/lib/gstreamer-0.10" ];
+    };
+
     environment.etc = singleton
       { source = "${pkgs.xkeyboard_config}/etc/X11/xkb";
         target = "X11/xkb";