gamescope: split vulkan layer into lib output

Signed-off-by: Sefa Eyeoglu <contact@scrumplex.net>

pkgs/applications/window-managers/gamescope/default.nix

@@ -106,6 +106,8 @@ stdenv.mkDerivation {
     libdisplay-info
   ];
 
+  outputs = [ "out" "lib" ];
+
   postUnpack = ''
     rm -rf source/subprojects/vkroots
     ln -s ${vkroots} source/subprojects/vkroots
@@ -114,7 +116,12 @@ stdenv.mkDerivation {
   # --debug-layers flag expects these in the path
   postInstall = ''
     wrapProgram "$out/bin/gamescope" \
-     --prefix PATH : ${with xorg; lib.makeBinPath [xprop xwininfo]}
+      --prefix PATH : ${with xorg; lib.makeBinPath [xprop xwininfo]}
+
+    # Install Vulkan layer in lib output
+    install -d $lib/share/vulkan
+    mv $out/share/vulkan/implicit_layer.d $lib/share/vulkan
+    rm -r $out/share/vulkan
   '';
 
   meta = with lib; {