It's an work in progress article so some things are not accurate or
will be corrected

http://firebirdnews.blogspot.com/2004/11/installing-firebird-on-freebsd.html

also we don't have an FreeBSD maintainer any more , the firebird port
is ancient (2.0.3)and must be updated to 2.0.5 or 2.1 later
in other bad news we also lost our Gentoo maintaner so firebird is
orphaned on Gentoo

ps:the good news we have an fedora port in progress and when is ready
i will publish on firebirdnews and here :)