[libwnck/wip/warnings3: 10/12] screen: avoid deprecated gdk_display_get_screen

[Alberts Muktupāvels <muktupavels src gnome org>]

commit b190a979fabc663d02fd4fffc48df5be53f902c0
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Fri Apr 28 14:51:29 2017 +0300

    screen: avoid deprecated gdk_display_get_screen
    
    GTK+ does not support multiple screens!

 libwnck/screen.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/libwnck/screen.c b/libwnck/screen.c
index 9ef3a1d..7798064 100644
--- a/libwnck/screen.c
+++ b/libwnck/screen.c
@@ -872,7 +872,10 @@ _wnck_screen_get_gdk_screen (WnckScreen *screen)
   if (!gdkdisplay)
     return NULL;
 
-  return gdk_display_get_screen (gdkdisplay, screen->priv->number);
+  if (screen->priv->number != 0)
+    return NULL;
+
+  return gdk_display_get_default_screen (gdkdisplay);
 }
 
 /**