Description:
------------
pathinfo() doesn't handle pathname in multibyte well. This error can be reporduced under big5 and utf-8 charset, no matter converting the whole source php file or using mb_convert_encoding() inline.
This error only occurs when the first character of basename is a Chinese character.

I didn't recompile PHP bin, and modules used seem not relevent. My php.ini is adapted from php.ini-recommended. The OS is a Traditional Chinese version.

Reproduce code:
---------------
<?php
$fp = '/var/????.txt';
var_dump(pathinfo($fp));
$fp = '/var/a????.txt';
var_dump(pathinfo($fp));
?>

Expected result:
----------------
array(3) {
  ["dirname"]=>
  string(4) "/var"
  ["basename"]=>
  string(8) "????.txt"
  ["extension"]=>
  string(3) "txt"
}
array(3) {
  ["dirname"]=>
  string(4) "/var"
  ["basename"]=>
  string(8) "a????.txt"
  ["extension"]=>
  string(3) "txt"
}

Actual result:
--------------
array(3) {
  ["dirname"]=>
  string(4) "/var"
  ["basename"]=>
  string(4) ".txt"
  ["extension"]=>
  string(3) "txt"
}
array(3) {
  ["dirname"]=>
  string(4) "/var"
  ["basename"]=>
  string(8) "a????.txt"
  ["extension"]=>
  string(3) "txt"
}