wrapGAppsHook: move to a separate file

pkgs/build-support/setup-hooks/wrap-gapps-hook/default.nix

@@ -0,0 +1,16 @@
+{ stdenv
+, lib
+, makeSetupHook
+, makeWrapper
+, gtk3
+, librsvg
+, dconf
+}:
+
+makeSetupHook {
+  deps = lib.optional (!stdenv.isDarwin) dconf.lib ++ [
+    gtk3
+    librsvg
+    makeWrapper
+  ];
+} ./wrap-gapps-hook.sh

pkgs/top-level/all-packages.nix

@@ -502,9 +502,7 @@ in
 
   findXMLCatalogs = makeSetupHook { } ../build-support/setup-hooks/find-xml-catalogs.sh;
 
-  wrapGAppsHook = makeSetupHook {
-    deps = lib.optional (!stdenv.isDarwin) dconf.lib ++ [ gtk3 librsvg makeWrapper ];
-  } ../build-support/setup-hooks/wrap-gapps-hook.sh;
+  wrapGAppsHook = callPackage ../build-support/setup-hooks/wrap-gapps-hook { };
 
   separateDebugInfo = makeSetupHook { } ../build-support/setup-hooks/separate-debug-info.sh;