bdasup: Addendum to 40c15ec (r46632).
kmixer: Addendum to 3e489bf (r42143).
mmixer: Addendum to c42d9f2 (r44872).
stream: Addendum to 4a0debf (r41662).
Serge plans a follow up that will remove all other remaining YDEBUG in the source tree.
The ones covered here he considered to be the most trivial ones.