anchor.diff:    ];
   
     configureFlags = [
  -    "--enable-introspection"
  -  ] ++ lib.optionals (!stdenv.isDarwin) [
  +    (lib.enableFeature withIntrospection "introspection")
  +
       # Vapi does not build on MacOS.
       # https://github.com/NixOS/nixpkgs/pull/117081#issuecomment-827782004
  -    "--enable-vala"
  -  ] ++ [
  +    (lib.enableFeature (withIntrospection && !stdenv.isDarwin) "vala")
  +
       "--enable-installed-tests"
       "--enable-always-build-tests"
     ] ++ lib.optional stdenv.isDarwin "--disable-Bsymbolic";
  
positive.code:     bzip2
      pango
      libintl
      gobject-introspection
    ] ++ lib.optionals stdenv.isDarwin [
      libobjc
  
negative.code:     rustc
      cargo
      vala
      rustPlatform.cargoSetupHook
    ] ++ lib.optionals withIntrospection [
      gobject-introspection
    ] ++ lib.optionals stdenv.isDarwin [
      ApplicationServices
  