Log Message:
mencoder, mplayer, gmplayer: use /dev/audio for OSS on NetBSD/OpenBSD.

- See PR/54229 about misuse of NetBSD's /dev/sound for OSS.
- OpenBSD's /dev/sound seems removed since 6.1:
  https://man.openbsd.org/OpenBSD-6.1/audio.4

Bump PKGREVISIONs.