Ardour 3.x: ports/180171 adds its new dependencies

[Marcel Bonnet]

Hi!

I want to announce I'm working on final steps for a port of Ardour 3.1 .
In case we have a ports commiter (in this list) available to take a look at
the PR 180171, it adds 6 new ports - new dependencies required by Ardour 3.
Ardour 3, itself, was not yet submitted.

Cheers,
-- 
Marcel Bonnet