Description:
------------
unpack is wrong in 5.2.1 on my x86_64 box.
in 5.2.0 it was OK.

Reproduce code:
---------------
<?php
$v = pack("N", 4816);
var_dump(unpack('N', $v));
?>


Expected result:
----------------
array(1) {
 [1]=>
 int(4816)
} 


Actual result:
--------------
array(1) {
 [1]=>
 int(-2147478832)
}