[SDL] ALSA/OSS linux audio driver priorities

[Sam Lantinga]

> I believe the attached patch should make ALSA preferred over OSS.

The reason it wasn't preferred in the past is that there were bugs
with ALSA hanging on open when (real) OSS was being used, but some
OSS drivers would allow multiple opens.

There were also audio quality and latency problems with ALSA that
weren't present in the OSS emulation.

I don't know if these are still the case...

See ya,
	-Sam Lantinga, Lead Software Engineer, Blizzard Entertainment