Description:
------------
F:/Some/Dir/PHP/php.exe -S 127.0.0.1:8888 -t W:/Web/Dir/root W:/Web/Dir/root/router.php

(meaning: PHP must use /root as directory. And use router.php as a simple check.)

Test script:
---------------
router.php
---
<?php
print_r($_SERVER);
?>
---

Expected result:
----------------
[SCRIPT_FILENAME] => W:/Web/Dir/root/router.php

Actual result:
--------------
[SCRIPT_FILENAME] => W:\Web\Dir\root/W:/Web/Dir/root/router.php