qt6.qtdeclarative: slightly less bad hack to make it build on Darwin again

pkgs/development/libraries/qt-6/modules/qtdeclarative.nix

@@ -4,24 +4,27 @@
 , qtshadertools
 , openssl
 , stdenv
-, python3
 , lib
 , pkgsBuildBuild
 }:
 
 qtModule {
   pname = "qtdeclarative";
-  strictDeps = !stdenv.isDarwin; # fails to detect python3 otherwise
+
   propagatedBuildInputs = [ qtbase qtlanguageserver qtshadertools openssl ];
-  nativeBuildInputs = [ python3 ];
+  strictDeps = true;
+
   patches = [
     # prevent headaches from stale qmlcache data
     ../patches/0001-qtdeclarative-disable-qml-disk-cache.patch
     # add version specific QML import path
     ../patches/0002-qtdeclarative-also-use-versioned-qml-paths.patch
   ];
+
   cmakeFlags = [
     "-DQt6ShaderToolsTools_DIR=${pkgsBuildBuild.qt6.qtshadertools}/lib/cmake/Qt6ShaderTools"
+    # for some reason doesn't get found automatically on Darwin
+    "-DPython_EXECUTABLE=${lib.getExe pkgsBuildBuild.python3}"
   ]
   # Conditional is required to prevent infinite recursion during a cross build
   ++ lib.optionals (!stdenv.buildPlatform.canExecute stdenv.hostPlatform) [