Description:
------------
This change of PHP Manual example results in Apache crash. 
Apache/1.3.27, PHP 5.2.5. PHP4 - the same.

Reproduce code:
---------------
<?php
$arResults = array();

$text = "April fools day is 04/01/2002\n";
$text .= "Last christmas was 12/24/2001\n";
function next_year($matches) 
{
	global $arResults;
	$arResults[] = $matches;
	return $matches[2];
}

echo preg_replace_callback(
	"/(April|Last) ([\S]*)/",
	"next_year",
	$text);

echo '<pre>'; print_r($arResults); echo '</pre>';
?> 

Expected result:
----------------
fools day is 04/01/2002 christmas was 12/24/2001

Array
(
    [0] => Array
        (
            [0] => April fools
            [1] => April
            [2] => fools
        )

    [1] => Array
        (
            [0] => Last christmas
            [1] => Last
            [2] => christmas
        )

)


Actual result:
--------------
Apache crash