Description:
------------
Embedded server segfault when callback for header_register_callback is a method.

1. Create script.
2. Start embedded server with php -S 0.0.0.0:8080.
3. First curl request curl http://localhost:8080/foo succeed.
4. Second curl request (only when path differs!) curl http://localhost:8080/foobar fails.


Test script:
---------------
<?php

class Foo {

    public function __construct() {
        header_register_callback(array($this, 'headerCallback'));
    }

    public function headerCallback() {
        
    }

}
$foo = new Foo();

Expected result:
----------------
PHP 5.5.7 Development Server started at Tue Dec 31 12:40:41 2013
Listening on http://0.0.0.0:8080
Document root is /Users/Username/Sites/Projectname/Public
Press Ctrl-C to quit.
[Tue Dec 31 12:41:27 2013] 127.0.0.1:54151 [200]: /foo
[Tue Dec 31 12:41:27 2013] 127.0.0.1:54154 [200]: /foobar


Actual result:
--------------
PHP 5.5.7 Development Server started at Tue Dec 31 12:39:09 2013
Listening on http://0.0.0.0:8080
Document root is /Users/Username/Sites/Projectname/Public
Press Ctrl-C to quit.
[Tue Dec 31 12:40:39 2013] 127.0.0.1:54136 [200]: /foo
[Tue Dec 31 12:40:41 2013] 127.0.0.1:54139 [200]: /foobar
Segmentation fault: 11