Description:
------------
Giving post_max_size a value equal or greater than 2GB on 
php.ini causes php to overflow the variable it uses to store 
that value. The result is log entries similar to this:

"POST Content-Length of 0 bytes exceeds the limit of 
-2147483648 bytes"

Reproduce code:
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Set post_max_size to 2G or more on php.ini, execute a POST operation on a php script.

Expected result:
----------------
The POST operation should complete, according to the limits 
specified on php.ini

Actual result:
--------------
"POST Content-Length of 0 bytes exceeds the limit of 
-2147483648 bytes" or similar entries on the webserver 
logfile, POST fails.