Description:
------------
getgrouplist function is not posix standard, but available at most distros

Test script:
---------------
var_dump(posix_getgrouplist('root',0));

Expected result:
----------------
root:x:0:root
bin:x:1:root,bin,daemon
daemon:x:2:root,bin,daemon

array(3) {
  [0]=>
  int(0)
  [1]=>
  int(1)
  [2]=>
  int(2)
}



Actual result:
--------------
Call to undefined function posix_getgrouplist()