preg_match and shared libpcre3 bug

I know this is weird and off-topic but I hope that someone here can give me a starting pointer. With installing a security update for the pcre3 library on Debian (http://lists.debian.org/debian-security-announce/debian-security-announ ce-2007/msg00177.html), preg_match('|^\(|', 'xxx') suddenly returns 1 instead of 0 using PHP 5.1.6. The thing is - I have built PHP using the bundled PCRE library and the error happens only with the apache2 module, not with a CLI binary. phpinfo() shows PCRE 6.6 and ldd shows no dependencies against the shared libpcre.so.3, neither for the php-cli binary nor for the apache module. Any ideas what might cause that? I can't see why the shared library update makes a difference at all. Thanks! -mp.