ffmpeg with libfdk_aac2 support

[jdhedden]

I would like to request the addition of libfdk_aac2 support in ffmpeg.

I am currently using the Debian Stretch version of ffmpeg to get fdk_acc support. However, the packages that were upgraded as a result of installing ffmpeg from Stretch have broken GIMP for me. (And if I continue with upgrading GIMP from Stretch, the rabbit hole just keeps getting deeper.)

[Stevo]

The Debian and ffmpeg developers say that ffmpeg's own aac encoder is improved enough to render that outside library obsolete.