[gnome-settings-daemon] power: Fix "undefined symbol: WEXITSTATUS" error.

[Bastien Nocera <hadess src gnome org>]

commit 6fa069f0f2c2337acd7fd1335a91554765253741
Author: Malcolm Lewis <malcolmlewis opensuse org>
Date:   Mon Oct 17 11:43:06 2011 -0500

    power: Fix "undefined symbol: WEXITSTATUS" error.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=662020

 plugins/power/gsd-power-manager.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/plugins/power/gsd-power-manager.c b/plugins/power/gsd-power-manager.c
index a5fc50d..27e1285 100644
--- a/plugins/power/gsd-power-manager.c
+++ b/plugins/power/gsd-power-manager.c
@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
+#include <sys/wait.h>
 #include <glib/gi18n.h>
 #include <gtk/gtk.h>
 #include <libupower-glib/upower.h>