(X)MAME can't really be considered free, as there are some
limitations as
to how it or any derivative work can be (re)distributed. Basically, you
can't charge for MAME in any shape or form. This is mainly to avoid having
companies selling some kind of "arcade game console" which would be running
MAME. Please check out the full license at
http://www.mame.net/ for more
precise information.
You're right. From the FAQ, it says that's it's free to re-distribute
but that you can't sell it. That said, I think it's free _enough_ to
have it in anvil's repository.
--
Julien Olivier <julo(a)altern.org>