pulseaudio: Add PACKAGECONFIG for optional OSS support

pulseaudio: Add PACKAGECONFIG for optional OSS support

Add pulseaudio PACKAGECONFIG for optional OSS (Open Sound System) output
support. OSS was a sound system available before ALSA and has since been
deprecated. Lately, this part has started causing build issues when used
with GLIBC_64BIT_TIME_FLAGS. Thus, by default drop OSS output support in
favor of Y2038 compliance.

Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>