[libwnck] core: Fix build for people without xres

[Vincent Untz <vuntz src gnome org>]

commit 375712fb492bd76495e02d1ade6c7a651b70fdbc
Author: Vincent Untz <vuntz gnome org>
Date:   Tue Jan 31 15:24:38 2012 +0100

    core: Fix build for people without xres

 libwnck/util.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/libwnck/util.c b/libwnck/util.c
index 1e16862..a2bb8c4 100644
--- a/libwnck/util.c
+++ b/libwnck/util.c
@@ -827,8 +827,10 @@ wnck_shutdown (void)
   _wnck_screen_shutdown_all ();
   _wnck_window_shutdown_all ();
 
+#ifdef HAVE_XRES
   if (xres_removeid != 0)
     g_source_remove (xres_removeid);
   xres_removeid = 0;
   wnck_pid_read_resource_usage_destroy_hash_table (NULL);
+#endif
 }