patch 8.2.0523: loops are repeated

Problem:    Loops are repeated.
Solution:   Use FOR_ALL_ macros. (Yegappan Lakshmanan, closes #5882)
diff --git a/src/gui_gtk.c b/src/gui_gtk.c
index 152f068..fa63bf9 100644
--- a/src/gui_gtk.c
+++ b/src/gui_gtk.c
@@ -824,7 +824,7 @@
     vimmenu_T	*menu;
     char_u	*name;
 
-    for (menu = root_menu; menu != NULL; menu = menu->next)
+    FOR_ALL_MENUS(menu)
     {
 	if (menu->id == NULL)
 	    continue;