[gtk+/gtk-3-4] statusicon: Fix implicit declaration warning

[Cosimo Cecchi <cosimoc src gnome org>]

commit 375a297b2c4f9f2e61b6867e12e3b1dd151777e7
Author: Bastien Nocera <hadess hadess net>
Date:   Tue May 15 17:55:36 2012 +0100

    statusicon: Fix implicit declaration warning
    
    gtkstatusicon.c:1333:4: warning: implicit declaration of function 'abs' [-Wimplicit-function-declaration]
    
    Added in commit c8378099600e4279cb5c608b546bbe778c451233

 gtk/gtkstatusicon.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkstatusicon.c b/gtk/gtkstatusicon.c
index efecdad..5c8a591 100644
--- a/gtk/gtkstatusicon.c
+++ b/gtk/gtkstatusicon.c
@@ -28,6 +28,7 @@
 #include "config.h"
 
 #include <string.h>
+#include <stdlib.h>
 
 #include "gtkstatusicon.h"