[gtk+] Deal with broken _NET_WORKAREA more gracefully

[Matthias Clasen <matthiasc src gnome org>]

commit f759523a302adcfb3297a6b813f753f4886a8775
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Jan 4 15:15:00 2014 -0500

    Deal with broken _NET_WORKAREA more gracefully
    
    fvwm seems to have problems keeping _NET_WORKAREA in sync with
    the number of desktops. Instead of reading garbage, silently use
    the full screen as workarea for desktops that are not covered
    by the _NET_WORKAREA property.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=698248

 gdk/x11/gdkscreen-x11.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gdk/x11/gdkscreen-x11.c b/gdk/x11/gdkscreen-x11.c
index 9f09ce1..31e5688 100644
--- a/gdk/x11/gdkscreen-x11.c
+++ b/gdk/x11/gdkscreen-x11.c
@@ -359,6 +359,8 @@ get_work_area (GdkScreen    *screen,
     goto out;
 
   desktop = get_current_desktop (screen);
+  if (desktop + 1 > num / 4) /* fvwm gets this wrong */
+    goto out;
 
   workareas = (long *) ret_workarea;
   area->x = workareas[desktop * 4];