Merge pull request #20428 from ttuegel/multiple-outputs-gtk

Use multiple outputs for gtkmm and friends

pkgs/development/python-modules/pygobject/3.nix

@@ -10,6 +10,8 @@ mkPythonDerivation rec {
     sha256 = "08b29cfb08efc80f7a8630a2734dec65a99c1b59f1e5771c671d2e4ed8a5cbe7";
   };
 
+  outputs = [ "out" "dev" ];
+
   buildInputs = [ pkgconfig glib gobjectIntrospection ]
                  ++ stdenv.lib.optionals stdenv.isDarwin [ which ncurses ];
   propagatedBuildInputs = [ pycairo cairo ];