ports/109379: ffmpeg-devel can't dynamically link to faad2

[Bill Fenner]

While faad 2.5,1 includes API compatability,
as I stated in the description of the problem,
the linkage that ffmpeg uses is not able to
use that API compatability.  This is because
the faad API compatability is performed with
#defines, and the ffmpeg linkage happens with
fancy macros that put together the function
names in a way that doesn't allow the #defines
to work.

(The dfaac() macro in libavcodec/faad.c
uses "faacDec" ## a to put symbols together
to get, e.g. faacDecGetErrorMessage, into
strings, which it then looks up in the shared
library with dlsym(), which never gives the
"compatability API" a chance to get in the
middle).

Were you able to get the steps in "how-to-repeat:"
to work, or did you just close the PR because
you think it is supposed to work?  I think it is
supposed to work too, but that doesn't mean it does.

I spent an hour rebuilding faad (of which I already
had 2.5,1 installed) and ffmpeg-devel (which I upgraded
from ffmpeg-devel-0.4.9.c.2006032300_4 to
ffmpeg-devel-0.4.9.c.2006032300_5) to make sure that
the bug was still there.

frogbits% pkg_info -I ffmpeg\* faad\*
faad2-2.5,1         MPEG-2 and MPEG-4 AAC audio decoder
ffmpeg-devel-0.4.9.c.2006032300_5 Hyper fast realtime audio/video encoder/converter, streamin
frogbits% ffmpeg -i Diego-2.mp4 /tmp/foo.mpeg
FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --cc=cc --prefix=/usr/local --make=gmake --disable-debug --enable-memalign-hack --enable-shared --source-path=/usr/ports/multimedia/ffmpeg-devel/work/FFMpeg-2006032300 --enable-a52 --enable-dts --enable-faac --enable-faad --enable-faadbin --enable-gpl --enable-libgsm --enable-mp3lame --enable-libogg --enable-pp --enable-pthreads --enable-vorbis --enable-x264 --enable-xvid 
  libavutil version: 49.0.0
  libavcodec version: 51.8.0
  libavformat version: 50.4.0
  built on Apr  2 2007 10:02:29, gcc: 3.4.4 [FreeBSD] 20050518

Seems that stream 0 comes from film source: 24000.00 (24000/1) -> 23.98 (24000/1001)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Diego-2.mp4':
  Duration: 00:42:45.1, start: 0.000000, bitrate: 1129 kb/s
  Stream #0.0(eng), 23.98 fps(r): Video: mpeg4, yuv420p, 640x480
  Stream #0.1(eng): Audio: aac, 44100 Hz, stereo
Output #0, mpeg, to '/tmp/foo.mpeg':
  Stream #0.0, 23.98 fps(c): Video: mpeg1video, yuv420p, 640x480, q=2-31, 200 kb/s
  Stream #0.1: Audio: mp2, 44100 Hz, stereo, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
[aac @ 0x28356028]FAAD library: cannot resolve faacDecGetErrorMessage in libfaad.so.0!
Error while opening codec for input stream #0.1


  Bill