[mutter] cursor-tracker: Check for NULL coordinates before retrieving them

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit aff14eab866a98907ab6bee51dec707365f67ce1
Author: Daniel van Vugt <daniel van vugt canonical com>
Date:   Wed Oct 28 17:29:48 2020 +0800

    cursor-tracker: Check for NULL coordinates before retrieving them
    
    This makes Wayland consistent with X11 in not emitting warnings when
    unwanted parameters are NULL.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1519

 src/backends/meta-cursor-tracker.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/src/backends/meta-cursor-tracker.c b/src/backends/meta-cursor-tracker.c
index 943949d4a7..c6afd75c32 100644
--- a/src/backends/meta-cursor-tracker.c
+++ b/src/backends/meta-cursor-tracker.c
@@ -501,7 +501,9 @@ get_pointer_position_clutter (graphene_point_t *point,
   seat = clutter_backend_get_default_seat (clutter_get_default_backend ());
   cdevice = clutter_seat_get_pointer (seat);
 
-  clutter_input_device_get_coords (cdevice, NULL, point);
+  if (point)
+    clutter_input_device_get_coords (cdevice, NULL, point);
+
   if (mods)
     *mods = clutter_input_device_get_modifier_state (cdevice);
 }