[Bug 44277] WOLF RPG Editor: Certain background music doesn' t stop when using XAudio2

https://bugs.winehq.org/show_bug.cgi?id=44277

--- Comment #6 from Andrew Eikum  ---
(In reply to kakurasan from comment #5)
> The hack works for me, but I think this is not "proper" fix because
> this is a hack for limited cases. However, I don't know how to set
> volume per channel with OpenAL API.

I'd be OK with a partial implementation like that. It could use some tests,
input validation, and I'd probably use a do-while instead of the if(i>0) bit.

In the case where the volumes are not the same, I think we should WARN. It
might make sense to average the volumes as an approximation. Or maybe take the
lowest, or do nothing, I don't know. In practice I suspect few applications
actually use this feature.