In php.ini
I have:
extension_dir = \"/usr/lib/php/extensions\"
However, running php-config
gives:
--e
It's an extension directory for PHP, named after some factors that influence extension compatibility: thread safety (non-zts), debug (no-debug), and engine version (20090626).
I recommend against changing the path. If it doesn't exist, create it, and put your extensions there. It's also where PECL will install extensions.