threads: warn in case of multiple finished setup calls.

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

libavcodec/pthread.c

@@ -599,6 +599,10 @@ void ff_thread_finish_setup(AVCodecContext *avctx) {
 
     if (!(avctx->active_thread_type&FF_THREAD_FRAME)) return;
 
+    if(p->state == STATE_SETUP_FINISHED){
+        av_log(avctx, AV_LOG_WARNING, "Multiple ff_thread_finish_setup() calls\n");
+    }
+
     pthread_mutex_lock(&p->progress_mutex);
     p->state = STATE_SETUP_FINISHED;
     pthread_cond_broadcast(&p->progress_cond);