qttools: patch qmlimportscanner for darwin builds

This needs to be the full path for qtmacdeploy to work. We add
${qt5.qttools.dev}/bin/qmlimportscanner as the default.

Fixes #63093

pkgs/development/libraries/qt-5/modules/qttools.nix

@@ -1,4 +1,4 @@
-{ qtModule, stdenv, lib, qtbase }:
+{ qtModule, stdenv, lib, qtbase, qtdeclarative }:
 
 with lib;
 
@@ -32,5 +32,8 @@ qtModule {
     "bin/macdeployqt"
   ];
 
+  NIX_CFLAGS_COMPILE =
+    lib.optional stdenv.isDarwin ''-DNIXPKGS_QMLIMPORTSCANNER="${qtdeclarative.dev}/bin/qmlimportscanner"'';
+
   setupHook = ../hooks/qttools-setup-hook.sh;
 }