Merge commit '6427379f'

* commit '6427379f':
  als: Restructure DEBUG ifdefs to avoid unused function parameter warnings
  ac3enc: Restructure DEBUG ifdefs to avoid unused function parameter warnings
  ape: Restructure DEBUG ifdefs to avoid unused function parameter warnings

These 3 commits are not merged.

These commits were actually controversial in Libav. A good rationale can
be found here:
https://lists.libav.org/pipermail/libav-devel/2016-November/080698.htmMerged-by: Clément Bœsch <u@pkh.me>