Description:
------------
PHP segfaults using the given script.

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

$array = array('1' => 'one',
               '2' => 'two',
               '3' => 'three');

$object = new ArrayObject($array);
$arrayobject = new ArrayObject($object);

$arrayobject[] = 'four';
?>

Actual result:
--------------
$ gdb php
GNU gdb 2003-09-20-cvs (cygwin-special)
(...)
(gdb) run bug-spl.php
Starting program: /cygdrive/c/PHP/php.exe bug-spl.php
---Type <return> to continue, or q <return> to quit---

Program received signal SIGSEGV, Segmentation fault.
0x1003d8d3 in zend_bailout () from /cygdrive/c/PHP/php5ts.dll
(gdb) bt
#0  0x1003d8d3 in zend_bailout () from /cygdrive/c/PHP/php5ts.dll
#1  0x00a00278 in ?? ()
#2  0x00000002 in ?? ()
#3  0x00000001 in ?? ()
#4  0x00362680 in ?? ()
#5  0x10005189 in php5ts!add_next_index_null ()
   from /cygdrive/c/PHP/php5ts.dll