Description:
------------
PHP segfaults when running preg_match() with a simple pattern intended to match any sequence of characters which are not followed by a given character (lookahead assertion). The segfault only happens if the string being matched approaches 10k characters in length, but at that point it seems to be 100% reproducible.

Config line:
./configure --with-apxs2=/usr/local/apache2/bin/apxs --with-mysql --with-pgsql --enable-sockets --enable-debug

Reproduce code:
---------------
$strlen = 10000;
$string = '';
for($i=0;$i<$strlen;$i++) {
    $string .= "a";
}
$pattern = '/(.(?!b))*/';
echo preg_match($pattern, $string);

Expected result:
----------------
1

Actual result:
--------------
Segmentation fault. I can't seem to get gdb to behave right now, so if someone else could reproduce the bug and post a backtrace, that would be nice.