oguri: reduce supported platforms

This doesn't work on darwin which has no wayland support.

pkgs/tools/wayland/oguri/default.nix

···
     description = "A very nice animated wallpaper daemon for Wayland compositors";
     license = licenses.mit;
     maintainers = with maintainers; [ AndersonTorres ];
-    platforms = platforms.unix;
+    inherit (wayland.meta) platforms;
+    broken = stdenv.isDarwin; # this should be enfoced by wayland platforms in the future
   };
 }