[development] Object caching

[Khalid B]

>     if ($_menu = apc_fetch($cid)) {
>       //loaded menu from cache
>     } else {
>       _menu_build();
>       apc_store($cid,$_menu,36000);
>     }

Is it worth it considering this and other performance tweeks and
making them into a .inc that checks for function_exists() and
uses APC  (or memcached or what have you)?