Bug 591859 - Use glib/gi18n-lib to get correct gettext package

We need to use the -lib variant which in turn uses the
GETTEXT_PACKAGE define, because the default translation
domain is actually mutter, not gnome-shell.

src/shell-global.c

@@ -15,7 +15,7 @@
 #include <unistd.h>
 #include <dbus/dbus-glib.h>
 #include <gio/gio.h>
-#include <glib/gi18n.h>
+#include <glib/gi18n-lib.h>
 #include <math.h>
 #include <X11/extensions/Xfixes.h>