Description:
------------
Used PHP v5.0.5
When you create a class by extending ffi and add a
destructor to it, it doesn't get called when the object gets out of scope.

Reproduce code:
---------------
<?

class test extends ffi
{
    function __construct( $param ){ parent::__construct($param); echo
"born\n"; }
    function __destruct() { parent::__destruct(); echo "died\n"; }
}

$test = new test;
unset($test);

?>

Expected result:
----------------
born
died

Actual result:
--------------
born