audio: Add sndio backend

sndio is the native API used by OpenBSD, although it has been ported to
other *BSD's and Linux (packages for Ubuntu, Debian, Void, Arch, etc.).

Signed-off-by: Brad Smith <brad@comstyle.com>
Signed-off-by: Alexandre Ratchov <alex@caoua.org>
Reviewed-by: Volker RĂ¼melin <vr_qemu@t-online.de>
Tested-by: Volker RĂ¼melin <vr_qemu@t-online.de>
Message-Id: <YxibXrWsrS3XYQM3@vm1.arverb.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
diff --git a/audio/audio.c b/audio/audio.c
index cfa4119..5600593 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -2030,6 +2030,7 @@
         CASE(OSS, oss, Oss);
         CASE(PA, pa, Pa);
         CASE(SDL, sdl, Sdl);
+        CASE(SNDIO, sndio, );
         CASE(SPICE, spice, );
         CASE(WAV, wav, );