Painful Problem CI-3.0.1: register_long_arrays

Hello,

I'm getting this error and I can't find a solution I don't even know how to fix it:

A PHP Error was encountered
Severity: Core Error
Message: Directive 'register_long_arrays' is no longer available in PHP
Filename: Unknown
Line Number: 0

I'm using:

HTTP/1.1 500 Internal Server Error
Server: nginx/1.5.0
Date: Thu, 01 Oct 2015 20:33:35 GMT
Content-Type: text/html; charset=UTF-8
Connection: keep-alive
X-Powered-By: PHP/5.5.9-1ubuntu4.6


register_long_arrays is a very outdated config and is no longer available in php.ini

I'm using a shared server and I can't turn on or off this option.

I would like to know where I can disable it in CodeIgniter core.

Thanks for any hint.