Pass on MapNotify events to Clutter

Clutter needs to know about MapNotify events otherwise it will never
make the stage visible and nothing will paint.

src/compositor/mutter/compositor-mutter.c

@@ -1672,7 +1672,8 @@ clutter_cmp_manage_screen (MetaCompositor *compositor,
                PointerMotionMask |
                PropertyChangeMask |
                ButtonPressMask | ButtonReleaseMask |
-               KeyPressMask | KeyReleaseMask;
+               KeyPressMask | KeyReleaseMask |
+               StructureNotifyMask;
 
   if (XGetWindowAttributes (xdisplay, xwin, &attr))
       {
@@ -1837,6 +1838,11 @@ clutter_cmp_process_event (MetaCompositor *compositor,
 
   meta_error_trap_pop (xrc->display, FALSE);
 
+  /* Clutter needs to know about MapNotify events otherwise it will
+     think the stage is invisible */
+  if (event->type == MapNotify)
+    clutter_x11_handle_event (event);
+
   /* The above handling is basically just "observing" the events, so we return
    * FALSE to indicate that the event should not be filtered out; if we have
    * GTK+ windows in the same process, GTK+ needs the ConfigureNotify event, for example.