Add sofalizer for binaural transcoding

[athendrix]

You should add the sofalizer filter to your build script.
Particularly since your build can be used to add fdk_aac encoding, this is one of the only ways to transcode high quality binaural aac

It's in most of the default builds for various distributions already, and I was surprised to find you were missing it.

You need libmysofa and the --enable-libmysofa parameter.