gtk3: don't multiout demos

pkgs/development/libraries/gtk+/3.x.nix

@@ -154,17 +154,13 @@ stdenv.mkDerivation rec {
     done
   '';
 
-  # Make all demo related things in dev
-  postFixup =  ''
-    moveToOutput share/icons/hicolor "$dev"
-    moveToOutput share/applications "$dev"
-    moveToOutput share/gsettings-schemas "$dev"
-
+  # Wrap demos
+  postFixup =  optionalString (!stdenv.isDarwin) ''
     demos=(gtk3-demo gtk3-demo-application gtk3-icon-browser gtk3-widget-factory)
 
     for program in ''${demos[@]}; do
       wrapProgram $dev/bin/$program \
-        --prefix XDG_DATA_DIRS : "$GSETTINGS_SCHEMAS_PATH:$dev/share/gsettings-schemas/${pname}-${version}"
+        --prefix XDG_DATA_DIRS : "$GSETTINGS_SCHEMAS_PATH:$out/share/gsettings-schemas/${pname}-${version}"
     done
   '';