Description:
------------
array_intersect_key() seems undefined.

Reproduce code:
---------------
<?php
$array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
$array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'  => 8);

var_dump(array_intersect_key($array1, $array2));
?> 

Expected result:
----------------
array(2) {
  ["blue"]=>
  int(1)
  ["green"]=>
  int(3)
})

Actual result:
--------------
Fatal error: Call to undefined function array_intersect_key() in D:\Inetpub\wwwroot\phpbugs\array_intersect_key.php on line 13