Description:
------------
I'm using the __autoload function to load my package's files.  However, if I use another package and that has also implemented __autoload then PHP barfs

Would it be possible to create a stack of __autoload functions?  As an alternative, perhaps we could link __autoload methods to class definitions, and then check class definitions for __autoload functions whenever a class is not found.

Reproduce code:
---------------
<?php
// Test1.php
function __autoload() {}

?>

<?php
//Test2.php
include_once 'Test1.php';
function __autoload() {}

?>

Expected result:
----------------
When user tries to instanciate undefined classes the engine checks all __autoload() functions to try to load the class file.

Actual result:
--------------
Fatal error: Cannot redeclare __autoload() (previously declared in C:\Apache\Apache2\htdocs\DomTools\test.php:5) in C:\Apache\Apache2\htdocs\DomTools\autoload.php on line 7