Log Message:
musicpd: update to 0.20.12.

ver 0.20.12 (2017/11/25)
* database
  - upnp: adapt to libupnp 1.8 API changes
* input
  - cdio_paranoia, ffmpeg, file, smbclient: reduce lock contention,
    fixing lots of xrun problems
  - curl: fix seeking
* decoder
  - ffmpeg: fix GCC 8 warning
  - vorbis: fix Tremor support
* player
  - log message when decoder is too slow
* encoder
  - vorbis: default to quality 3
* output
  - fix hanging playback with soxr resampler
  - httpd: flush encoder after tag; fixes corrupt Vorbis stream