php.ini crashes CP with "Craft requires the PDO extension to operate." I'm trying to use php.ini to increase memory_limit etc on my site. An empty php.ini causes the front end to crash throwing a "Service Unavailable" error and the CP to throw the error "Craft requires the PDO extension to operate."

The server allows for php.ini files to be used. There is no craft/storage/logs/phperrors.log file and the PHP and apache logs don't seem to show anything.

Another user had the similar issue here but there doesn't seem to be a fix posted that works: Adding php.ini file to root crashes site

Thanks!
I fixed this by adding the PDO extensions in to my php.ini which was overriding the server one.

extension = "pdo.so"
extension = "pdo_sqlite.so"
extension = "apc.so"
extension = "intl.so"
extension = "pdo_mysql.so"