fix for clients that set a custom_main_menu (A. Foss)

server/menu.c

@@ -39,6 +39,9 @@
 #include "screen.h"
 #include "widget.h"
 
+
+extern Menu * custom_main_menu;
+
 /** Basicly a patched version of LL_GetByIndex() that ignores hidden
  * entries completely. (But it takes a menu as an argument.) */
 static void *
@@ -137,6 +140,9 @@ menu_destroy (Menu *menu)
 	if (menu == NULL)
 		return;
 
+	if (custom_main_menu == menu)
+		custom_main_menu = NULL;
+
 	menu_destroy_all_items (menu);
 	LL_Destroy (menu->data.menu.contents);
 	menu->data.menu.contents = NULL;