xmobar: wrap ghc completely and not expose it to home.packages

nix/configurations/vanadium/home/xmobar.nix

@@ -1,15 +1,15 @@
 {pkgs, ...}: {
   home.packages = let
+    inherit (pkgs) lib;
+
     wrapped-xmobar = pkgs.symlinkJoin {
       name = "xmobar";
-      paths = with pkgs; [
-        # Xmobar wants ghc
-        (haskellPackages.ghcWithPackages (self: [
-          self.xmobar
-        ]))
-        # The executable
-        xmobar
-      ];
+      paths = [pkgs.xmobar];
+      buildInputs = [pkgs.makeWrapper];
+      postBuild = ''
+        wrapProgram $out/bin/xmobar \
+          --prefix PATH : "${lib.makeBinPath [pkgs.ghc]}"
+      '';
     };
   in [
     wrapped-xmobar