Dealing with DOCS that depends on DOXYGEN

Hello all,

What's the best way to deal with DOCS that depends in DOXYGEN to be builted?

I've saw some ports that have DOCS with implicit dependency on DOXYGEN but
most of the time DOCS are doing nothing with default ON with DOXYGEN
default OFF.

Some ports just don't have DOCS available, only DOXYGEN.

Any help will be welcome.

Thanks,

-- 
Nuno Teixeira
FreeBSD Committer (ports)