[mutter] x11-display: Add back _GTK_EDGE_CONSTRAINTS as supported hints

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

commit 2fe05d7c357a6a5b1bd1367f13313cdfd449fdfa
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Jan 3 17:57:06 2019 +0100

    x11-display: Add back _GTK_EDGE_CONSTRAINTS as supported hints
    
    It was dropped by accident in 1530f2751308eaeead81b5fe4e6c7add64b0a0c5,
    so lets add it back.
    
    Fixes: https://gitlab.gnome.org/GNOME/mutter/issues/423

 src/x11/meta-x11-display.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/x11/meta-x11-display.c b/src/x11/meta-x11-display.c
index 77fb091f6..6f31f237f 100644
--- a/src/x11/meta-x11-display.c
+++ b/src/x11/meta-x11-display.c
@@ -598,6 +598,7 @@ set_supported_hint (MetaX11Display *x11_display)
 
     x11_display->atom__GTK_FRAME_EXTENTS,
     x11_display->atom__GTK_SHOW_WINDOW_MENU,
+    x11_display->atom__GTK_EDGE_CONSTRAINTS,
   };
 
   XChangeProperty (x11_display->xdisplay,