Fix a null pointer dereference in the audio queue.

miniaudio.h

@@ -66416,7 +66416,9 @@ MA_API ma_result ma_audio_queue_read_pcm_frames(ma_audio_queue* pAudioQueue, voi
     }
     ma_spinlock_unlock(&pAudioQueue->lock);
 
-    *pFramesRead = frameCount;
+    if (pFramesRead != NULL) {
+        *pFramesRead = frameCount;
+    }
 
     /* Note that we never returning MA_AT_END for a queue because there isn't really a notion of it. */
     return MA_SUCCESS;