[gnome-shell] st-shadow: Define autoptr cleanup function for StShadow

[Jonas Ådahl <jadahl src gnome org>]

commit ca4d86e9e549982761d07a3e48320f20e2383343
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Mon Feb 25 15:53:25 2019 +0100

    st-shadow: Define autoptr cleanup function for StShadow
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/5

 src/st/st-shadow.h | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/st/st-shadow.h b/src/st/st-shadow.h
index 8173f34f4..2870d41dd 100644
--- a/src/st/st-shadow.h
+++ b/src/st/st-shadow.h
@@ -72,6 +72,8 @@ void      st_shadow_get_box  (StShadow              *shadow,
                               const ClutterActorBox *actor_box,
                               ClutterActorBox       *shadow_box);
 
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (StShadow, st_shadow_unref);
+
 
 GType     st_shadow_helper_get_type (void) G_GNUC_CONST;