Git\Index\getEntry caused SEGV when using 64bit linux machine.

[chobie]

reported by @vissi. thanks!

straight forward test code.

<?php
define("REPOSITORY_NAME","/git_index_test");
use Git\Repository;

$repository = new Repository(__DIR__ . REPOSITORY_NAME . "/.git");
$index = $repository->getIndex();
$entry = $index->getEntry(0);

Program received signal SIGSEGV, Segmentation fault.
zend_do_fcall_common_helper_SPEC (execute_data=0x7fff00000000) at /build/buildd/php5-5.3.5/Zend/zend_vm_execute.h:383
383     in /build/buildd/php5-5.3.5/Zend/zend_vm_execute.h

i've spend several hours but i couldn't fixed yet.
perhaps some function brake PHP mermoy.so i'll more trace deeply.