patch 7.4.1713

Problem:    GTK GUI doesn't work on Wayland.
Solution:   Specify that only the X11 backend is allowed. (Simon McVittie)

src/gui_gtk_x11.c

@@ -1679,6 +1679,12 @@ gui_mch_init_check(void)
     }
 #endif
 
+#if GTK_CHECK_VERSION(3,10,0)
+    /* Vim currently assumes that Gtk means X11, so it cannot use native Gtk
+     * support for other backends such as Wayland. */
+    gdk_set_allowed_backends ("x11");
+#endif
+
 #ifdef FEAT_GUI_GNOME
     if (gtk_socket_id == 0)
 	using_gnome = 1;