[gentoo-dev] doxygen Update

[Phil Bordelon]

As a semi-followup to the earlier mon update, I've updated
doxygen as well.  Like mon, I'm keeping it masked out, as
doxygen is a fairly heavily used package.  Anyone who makes
regular use of the doxygen package is encouraged to unmask
the latest version and let us know how it works.  I don't
use doxygen either, mind, but . . . ;)

Thanks, folks.

Phil / sunflare