[gnome-screensaver] Add missing header file

[Ray Strode <halfline src gnome org>]

commit 74bed4d91af225b3ad4aacd3b906888a9f79985d
Author: Ray Strode <rstrode redhat com>
Date:   Fri Feb 12 14:13:13 2010 -0500

    Add missing header file
    
    This fixes a compiler warning.

 src/gs-manager.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/gs-manager.c b/src/gs-manager.c
index a8a2262..0a1b670 100644
--- a/src/gs-manager.c
+++ b/src/gs-manager.c
@@ -24,6 +24,7 @@
 
 #include <time.h>
 #include <gdk/gdk.h>
+#include <gdk/gdkx.h>
 
 #include <gconf/gconf-engine.h>
 #include <gconf/gconf-client.h>