    Merge remote-tracking branch 'ffmpeg-mt/master'

    * ffmpeg-mt/master:
DUPLICATE mingw32 compilation after 'unbreak avcodec_thread_init'
      pthread: validate_thread_parameters() ignored slice-threading being intentionally off
DUPLICATE Remove unnecessary parameter from ff_thread_init() and fix behavior

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
