git version 2.4.0
Removing ffbuild/config.log
From https://git.ffmpeg.org/ffmpeg
 * branch            master     -> FETCH_HEAD
HEAD is now at cd21fa4 avformat/aviobuf: Don't pretend to support avio_context_free(NULL)
cd21fa41c70bdc03660e0566649e9cf2bd7441b7