vf_interlace: check one av_frame_clone allocation

libavfilter/vf_interlace.c

@@ -185,6 +185,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
         av_log(ctx, AV_LOG_WARNING,
                "video is already interlaced, adjusting framerate only\n");
         out = av_frame_clone(s->cur);
+        if (!out)
+            return AVERROR(ENOMEM);
         out->pts /= 2;  // adjust pts to new framerate
         ret = ff_filter_frame(outlink, out);
         s->got_output = 1;