Description:
------------
With objects storing an array with key values >= 2e31  
(2147483648), these keys are altered after a serialize +  
unserialize.  
  
Occurs only on 64bit systems.  
  

Reproduce code:
---------------
class Test {
  var $arr = array() ;
  function define_tab() {
    $noscde = "5000000000" ;
    $this->arr[$noscde]['noscde'] = $noscde ;
  }
  function get_tab() { return $this->arr; }
}
$obj = new Test() ;
$obj->define_tab() ;
print_r( $obj->get_tab() ) ;
$pok = serialize( $obj ) ;
$obj = unserialize( $pok ) ;
print_r( $obj->get_tab() ) ;


Expected result:
----------------
Array ( [5000000000] => Array ( [noscde] => 5000000000 ) ) 
Array ( [5000000000] => Array ( [noscde] => 5000000000 ) ) 

Actual result:
--------------
Array ( [5000000000] => Array ( [noscde] => 5000000000 ) ) 
Array ( [705032704] => Array ( [noscde] => 5000000000 ) )