select XORG rather than depend on it.

package/libgtk2/Config.in

@@ -7,7 +7,7 @@ config BR2_PACKAGE_LIBGTK2
 	select BR2_PACKAGE_JPEG
 	select BR2_PACKAGE_TIFF
 	select BR2_PACKAGE_PNG
-	depends BR2_PACKAGE_XORG
+	select BR2_PACKAGE_XORG
 	help
 	  The GTK+ version 2 graphical user interface library