enable mbstring by default

Hi. As the "full" unicode support went down with php6, wouldn't it be a logical step to enable the mbstring extension by default(maybe even turning it into a builtin ext like phar)? I think that mbstring is a pretty mature and stable extension, and there isn't much dependencies so I can't think of reason why we couldn't do it. Of course the mbstring.func_overload would still disabled by default (maybe exporting the mb functions to the 'utf8' namespace? :P), so it would be a backward compatible change. What do you think? ps: maybe it is too late for 5.4, but having it in trunk is still better than nothing. -- Ferenc Kovács @Tyr43l - http://tyrael.hu