AUX channels can link to any other channel but when AUX channels are
linked, they must match exactly.
Fixes some issues with split devices with aux channels.
Media-session itself uses ms.core, there are only two files that could
have a sub-topic but right now they don't use it (match-rules and
metadata).
The modules use the ms.mod.* namespace, so it's trivial to filter on
those.
Previous commit 69e935e unconditionally called pw_log_set_level() after
the option parsing. If pw_init() changed the logging level based on
PIPEWIRE_DEBUG, we'd now overwrite that change.
Call pw_log_set_level() only if -v is actually given on the commandline.
This means a commandline option will override PIPEWIRE_DEBUG if set but
that is intended.
Fixes 69e935e8a4
