FPM uses libevent to manage connections and signals. Minimum required version is libevent-1.4.11.
In order to enable FPM in your PHP build you need to add --enable-fpm to your configure line.
There are several other FPM-specific configure options (all of them optional):
--with-libevent-dir - path to libevent install prefix.
--with-fpm-user - set FPM user (default - nobody).
--with-fpm-group - set FPM group (default - nobody).