cursor-renderer: Add API to allow inhibiting HW cursor

There may be reasons to temporarly inhibit the HW cursor under certain
circumstances. Allow adding such inhibitations by adding API to the
cursor renderer to allow API users to add generic inhibitors with
whatever logic is deemed necessary.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/357

src/backends/native/meta-cursor-renderer-native.c

@@ -586,6 +586,10 @@ should_have_hw_cursor (MetaCursorRenderer *renderer,
   if (!cursor_sprite)
     return FALSE;
 
+  if (meta_cursor_renderer_is_hw_cursors_inhibited (renderer,
+                                                    cursor_sprite))
+    return FALSE;
+
   for (l = gpus; l; l = l->next)
     {
       MetaGpuKms *gpu_kms = l->data;