Description:
------------
Unable to extend the PDO class because __construct is final.

Reproduce code:
---------------
class MyPDO extends PDO
{

   function __construct($dsn, $user, $pass)
   {
      parent::__construct($dsn, $user, $pass);
   }

}

$PDO = new MyPDO($dsn, $user, $pass);

Expected result:
----------------
I would expect to be able to extend PDO. I realize that this 
is intended behavior to avoid a SEGV, but I think that there 
are legitimate reasons why people would want to extend PDO. Is 
it possible to address this a different way?

Actual result:
--------------
Fatal error: Cannot override final method PDO::__construct() 
in myfile on line myline