gimp-with-plugins: fix installing custom scripts

script-fu (Scheme) scripts are not actually loaded from $GIMP2_PLUGINDIR (lib/gimp/2.10) but $GIMP_DATADIR (share/gimp/2.10).

pkgs/applications/graphics/gimp/default.nix

@@ -145,7 +145,7 @@ in stdenv.mkDerivation rec {
     # used for determining plug-in installation paths
     majorVersion = "${lib.versions.major version}.0";
     targetPluginDir = "lib/gimp/${majorVersion}/plug-ins";
-    targetScriptDir = "lib/gimp/${majorVersion}/scripts";
+    targetScriptDir = "share/gimp/${majorVersion}/scripts";
 
     # probably its a good idea to use the same gtk in plugins ?
     gtk = gtk2;

pkgs/applications/graphics/gimp/wrapper.nix

@@ -17,6 +17,7 @@ in symlinkJoin {
     for each in gimp-${versionBranch} gimp-console-${versionBranch}; do
       wrapProgram $out/bin/$each \
         --set GIMP2_PLUGINDIR "$out/lib/gimp/2.0" \
+        --set GIMP2_DATADIR "$out/share/gimp/2.0" \
         --prefix GTK_PATH : "${gnome3.gnome-themes-extra}/lib/gtk-2.0" \
         ${toString extraArgs}
     done