configuring port

[Bradley Giesbrecht]

There are a couple ports (dovecot and bind9) that I want to install  
that do not have variants that match my needs.

My needs would be something like:

port install dovecot +mysql
port install bind9 +dlz-mysql

Is there some reading that someone could point me to that could help  
me with downloading and reconfiguring a port from macports?

I'm looking to take advantage of the macports patches and handling of  
dependies.

I'm somewhat familiar with freebsd ports and gentoo emerge.

Is there something equiveleant to freebsd port where I could run ./ 
configure --with-some_option?


TIA,
Brad