Support for MacOS

[aragilar]

Is your feature request related to a problem? Please describe.
It doesn't look like this supports MacOS, given how tied it is to avahi?

Describe the solution you'd like
There appears to be no easy way to point MacOS cups to an existing cups server without overwriting client.conf (which naturally breaks local-only printing). Adding MacOS support would fix this.

[tillkamppeter]

The easiest way here would be to replace the direct Avahi interaction by the new libcups API functions, in libcups2 from CUPS 2.5.x on and libcups3 (libcups repo, for CUPS 3.x).