emacs.pkgs.ghostel: further ease overrideAttrs of local bumps

Even with the changes from
99800dd6b5,
local bumps break if they need a different version of Zig, like the
upgrade from Zig 0.15 to 0.16 in
78f9fbc227.

Fix this by using finalAttrs for zig too, so it can be overridden along
with src and zigDeps.

pkgs/applications/editors/emacs/elisp-packages/manual-packages/ghostel/package.nix

@@ -10,13 +10,12 @@
 }:
 
 let
-  zig = zig_0_16;
-
   mkModule =
     {
       pname,
       version,
       src,
+      zig,
       zigDeps,
     }:
     stdenv.mkDerivation (finalAttrs: {
@@ -24,10 +23,11 @@ let
         pname
         version
         src
+        zig
         zigDeps
         ;
 
-      nativeBuildInputs = [ zig ] ++ lib.optionals stdenv.hostPlatform.isDarwin [ xcbuild ];
+      nativeBuildInputs = [ finalAttrs.zig ] ++ lib.optionals stdenv.hostPlatform.isDarwin [ xcbuild ];
 
       env.EMACS_INCLUDE_DIR = "${emacs}/include";
 
@@ -67,8 +67,9 @@ melpaBuild (finalAttrs: {
     hash = "sha256-upIcL4wf2zAc3/3QeERF619nSDml2wEZCOl6/XOaT3E=";
   };
 
-  # this can be put into mkModule, but we put it here to ease user overrideAttrs
-  zigDeps = zig.fetchDeps {
+  # these can be put into mkModule, but we put them here to ease user overrideAttrs
+  zig = zig_0_16;
+  zigDeps = finalAttrs.zig.fetchDeps {
     inherit (finalAttrs) src pname version;
     fetchAll = true;
     hash = "sha256-NcNp0FnMy6FfZ63+pwiTRCmJ8FIovJEOhNvxVr1+uSQ=";
@@ -91,6 +92,7 @@ melpaBuild (finalAttrs: {
       inherit (finalAttrs)
         version
         src
+        zig
         zigDeps
         ;
     };