Description:
------------
strtolower encoding problem in UTF-8 mode at Windows 7.

Reproduce code:
---------------
<?php

echo strtolower("H?LIO"); // returns: h&#65533;lio (error)
echo strtoupper("h?lio"); // returns H?LIO (ok)

?>

Expected result:
----------------
<?php
// expected results

echo strtolower("H?LIO"); // returns: h?lio
echo strtoupper("h?lio"); // returns H?LIO

?>

Actual result:
--------------
<?php

echo strtolower("H?LIO"); // returns: h&#65533;lio (error)
echo strtoupper("h?lio"); // returns H?LIO (ok)

?>