facebook/hhvm — pull request #3722 by SiebelsTim (2014-09-10 20:20:01+00:00)
Title: posix_getgrnam returns false when no group gound

getgrnam_r and getgrgid_r return zero on success and an error number on failure.
If no matching group was found they return 0 and store NULL in *result.

This fixes three zend tests. Two of them have the exact same content though (lol)