Description:
------------
Setting post_max_size to a value of 6144M or greater causes $_POST to fail, for example to log in and start a session with the simple code below:  

<?php
session_start();
$username = $_POST['username'];

$password = $_POST['password'];
...etc.
?>

It will also cause the login to phpMyAdmin to fail with the error message:

Warning: Unknown: POST Content-length of 81 bytes exceeds the limit of -2147483648 bytes in Unknown on line 0

At a guess, perhaps to due to the post_max_size variable type? Although 6144M is perhaps an excessive post size maximum, a comment in the php.ini file warning of the maximum limit would be helpful.   



Reproduce code:
---------------
Can be reproduced with the index.php page of phpMyAdmin 2.10.0.2 and above

Expected result:
----------------
Failed login when post_max_size >= 6144M