mesa-glu: Use separate outputs

pkgs/development/libraries/mesa-glu/default.nix

···
   buildInputs = [ pkgconfig ];
   propagatedBuildInputs = [ mesa_noglu ];
 
+  outputs = [ "out" "dev" ];
+
   meta = {
     description = "OpenGL utility library";
     homepage = http://cgit.freedesktop.org/mesa/glu/;