drop opencore-amr

[Jeremy Huddleston Sequoia]

On the ffmpeg side, see https://trac.macports.org/ticket/33503.

If you want to obsolete the port and drop support for it from the dependents, I think that would be fine.

> On Dec 31, 2017, at 8:58 AM, Jan Stary <hans at stare.cz> wrote:
> 
> https://github.com/macports/macports-ports/pull/1182
> Is anyone using opencore-amr at all? This is what grep says:
> 
> * We have audio/libfdk-aac which implements the same
> * `gstreamer010-gst-plugins-ugly` depends on it (nomaintainer)
> * `gstreamer1-gst-plugins-ugly` depends on it (nomaintainer)
> * `avidemux` depends on it (nomaintainer)
> * `ffmpeg` depends on it (cc maintainer)
> * `fmpeg-devel` depends on it (cc maintainer)
> 
> Is anyone actually using that functionality?
> The only use case I can remember is that early Android's
> voice recorder recorded into AMR by default (which is
> why I ported it), but I haven't used it since.
> 
> 	Jan
>