python3.pkgs.meson-python: populate python build flags with $mesonFlags

pkgs/development/python-modules/meson-python/add-build-flags.sh

@@ -0,0 +1,6 @@
+# Add all of mesonFlags to -Csetup-args for pypa builds
+for f in $mesonFlags; do
+  pypaBuildFlags+=" -Csetup-args=$f"
+  # This requires pip>23.0.1, see: https://meson-python.readthedocs.io/en/latest/how-to-guides/config-settings.html
+  pipBuildFlags+=" --config-settings=setup-args=$f"
+done

pkgs/development/python-modules/meson-python/default.nix

@@ -39,6 +39,9 @@ buildPythonPackage rec {
   ] ++ lib.optionals (pythonOlder "3.10") [
     typing-extensions
   ];
+  setupHooks = [
+    ./add-build-flags.sh
+  ];
 
   # Ugly work-around. Drop ninja dependency.
   # We already have ninja, but it comes without METADATA.