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>

libavcodec/pthread.c

@@ -877,7 +877,7 @@ static void validate_thread_parameters(AVCodecContext *avctx)
         avctx->active_thread_type = 0;
     } else if (frame_threading_supported && (avctx->thread_type & FF_THREAD_FRAME)) {
         avctx->active_thread_type = FF_THREAD_FRAME;
-    } else {
+    } else if (avctx->thread_type & FF_THREAD_SLICE) {
         avctx->active_thread_type = FF_THREAD_SLICE;
     }
 }