AVAHI to the list. This fixes the textproc/docproj build
seemingly following FLAVORS being added.
Specifically, the problem with the dependency chain here is:
- textproc/docproj depends on print/cups, which sets AVAHI=on
by default;
- net/avahi-app depends on devel/gobject-introspection, which
requires python3+;
- graphics/netpbm depends on graphics/mesa-libs, which can
only be built with python2.7;
- textproc/docproj depends on a number of graphics ports for
font rendering, etc.
MFC after: 3 days
MFC before: 12.0-BETA3
Sponsored by: The FreeBSD Foundation
4de042ec89