[mutter/wip/carlosg/xwayland-on-demand: 417/430] core: Do not synchronize stack with Xserver if there is no X11 Display

[Carlos Garnacho <carlosg src gnome org>]

commit 76fa352e41392793262f6705a605d01896a19271
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Dec 30 13:12:42 2018 +0100

    core: Do not synchronize stack with Xserver if there is no X11 Display
    
    We were assuming there is always a MetaX11Display, this step can simply be
    ignored if there not one.

 src/core/stack.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/core/stack.c b/src/core/stack.c
index 7ab590c98..4535d8502 100644
--- a/src/core/stack.c
+++ b/src/core/stack.c
@@ -1009,6 +1009,9 @@ stack_sync_to_xserver (MetaStack *stack)
   GList *tmp;
   GArray *hidden_stack_ids;
 
+  if (!stack->display->x11_display)
+    return;
+
   /* Bail out if frozen */
   if (stack->freeze_count > 0)
     return;