Reapply "package/ffmpeg: add support for pulseaudio"
This reverts commit fecc337d21f337a30ef7f9f448683d99c01fc245,
re-adding optional support for pulseuadio in ffmpeg.
This is possible now that the circular dependency:
pulseaudio -> libsoxr -> ffmpeg -> pulseaudio
has been broken between libsoxr and ffmpeg.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>