[Devel-en] Switch from lash to ladish for sound packages

[Giovanni Mariani]

Hi all...

This is the actual situation for sound packages using jack sound server 
(mostly softsynth or lv2 stuff): near all those packages are using the 
lash library for managing jack session; unfortunately this library is 
outdated (the last release was in 2009) and basically unmaintained (last 
commit in the devel tree was in July 2009).

However there is a suitable replacement: the LADI Session Handler (= 
ladish) by Nedko Arnaudov. This library is a complete rewrite of lash 
and is already use by various stuff from kxstudio, notably Claudia and 
Cadence (see: https://github.com/LADI/ladish/blob/master/README).
It's also more active (last git commit was in February 2021) and has an 
handy lash compatibility layer (liblash): all it should be needed to 
convert a package from lash to ladish is changing the references to lash 
and its headers in those for the ladish compatibility layer and its headers.
I already tried that change for a simple package (amsynth) and a bigger 
one (calf): the needed patches are only 4 lines long.

My plan: switch the Sound packages from using lash to using ladish (they 
are 9 or 10 in total) and be happy.
To do this for packages in Main (eg. calf), we also need to move ladish 
from Contrib in Main (already filed bug #12415 about this thing).

Thoughts?

GvM