Bug 1410266 - Explicitly include locale.h in OSPreferences_gtk.cpp. r=jfkthame

MozReview-Commit-ID: 23Q7xGGBMNT

--HG--
extra : rebase_source : 6cb5bc0284f5212c1289fd5d974ad2c7219878da

intl/locale/gtk/OSPreferences_gtk.cpp

@@ -4,6 +4,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include <locale.h>
 #include "OSPreferences.h"
 #include "dlfcn.h"
 #include "glib.h"