[gtk/gtk-3-24] Avoid a critical in the Emoji chooser

[Matthias Clasen <matthiasc src gnome org>]

commit 0459569b491a6530037632f8b1c25d90112ee5f1
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Apr 14 15:36:57 2020 -0400

    Avoid a critical in the Emoji chooser
    
    If event_widget is NULL, just dismiss the popover.
    
    https://gitlab.gnome.org/GNOME/gtk/-/issues/2199

 gtk/gtkpopover.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index a2d47b6281..318171f556 100644
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -1566,7 +1566,7 @@ gtk_popover_button_release (GtkWidget      *widget,
           event->y > child_alloc.y + child_alloc.height)
         gtk_popover_popdown (popover);
     }
-  else if (!gtk_widget_is_ancestor (event_widget, widget))
+  else if (!event_widget || !gtk_widget_is_ancestor (event_widget, widget))
     {
       gtk_popover_popdown (popover);
     }