Index: gtk+-2.18.1/gdk/x11/gdkinput-xfree.c
===================================================================
--- gtk+-2.18.1.orig/gdk/x11/gdkinput-xfree.c
+++ gtk+-2.18.1/gdk/x11/gdkinput-xfree.c
@@ -18,6 +18,7 @@
  */
 
 #include "config.h"
+#include <string.h>
 #include "gdkinputprivate.h"
 #include "gdkdisplay-x11.h"
 #include "gdkalias.h"