[CentOS] php with oci8 support

I am attempting to build php with oracle oci8 support. I've installed the oracle installclient basic and devel rpms. When kicking off the srpm buid I am using the following...

rpmbuild --with oci8 --rebuild php-4.3.9-3.8.src.rpm

While on an FC 4 box this works and I end up with a php-oci8 pkg that is fully functional. However on CentOS 4.1 the build isn't actually building with oci8 and fails with ....

File not found: /var/tmp/php-root/usr/lib/php4/oci8.so

I've played around with the spec file and it looks like this could be the culprit. Has anyone got this to work besides building from source?