Revert "slim: remove duplicate code"

This reverts commit f7d5e83abb.  It
breaks the Firefox and Xfce tests:

  in job ‘tests.firefox.x86_64-linux’:
  cannot coerce a boolean to a string

  in job ‘tests.xfce.x86_64-linux’:
  infinite recursion encountered

lib/maintainers.nix

@@ -37,7 +37,6 @@
   ianwookim = "Ian-Woo Kim <ianwookim@gmail.com>";
   iElectric = "Domen Kozar <domen@dev.si>";
   iyzsong = "Song Wenwu <iyzsong@gmail.com>";
-  JagaJaga = "Arseniy Seroka <ars.seroka@gmail.com>";
   jcumming = "Jack Cummings <jack@mudshark.org>";
   kkallio = "Karn Kallio <tierpluspluslists@gmail.com>";
   ktosiek = "Tomasz Kontusz <tomasz.kontusz@gmail.com>";

nixos/modules/services/x11/display-managers/slim.nix

@@ -85,9 +85,7 @@ in
       
       package = mkOption {
         type = types.package;
-        default = pkgs.slim.override { 
-          theme = slimThemesDir; 
-          };
+        default = pkgs.slim;
         description = ''
           Configure slim package.
         '';

pkgs/applications/display-managers/slim/default.nix

@@ -2,7 +2,18 @@
 , fontconfig, freetype, pam, dbus_libs, makeWrapper, pkgs, theme ? null }:
 
 let 
-  slimThemesDir = if theme == null then "$out/share/slim/themes" else theme;
+  slimThemesDir =
+      let
+        unpackedTheme = pkgs.stdenv.mkDerivation {
+          name = "slim-theme";
+          buildCommand = ''
+            ensureDir $out
+            cd $out
+            unpackFile ${theme}
+            ln -s * default
+          '';
+        };
+    in if theme == null then "$out/share/slim/themes" else unpackedTheme;
 in
 
 stdenv.mkDerivation rec {