sdlaudio: add -audiodev sdl,out.buffer-count option

Currently there is a crackling noise with SDL2 audio playback.
Commit bcf19777df: "audio/sdlaudio: Allow audio playback with
SDL2" already mentioned the crackling noise.

Add an out.buffer-count option to give users a chance to select
sane settings for glitch free audio playback. The idea was taken
from the coreaudio backend.

The in.buffer-count option will be used with one of the next
patches.

Signed-off-by: Volker RĂ¼melin <vr_qemu@t-online.de>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 9315afe5-5958-c0b4-ea1e-14769511a9d5@t-online.de
Message-Id: <20210110100239.27588-3-vr_qemu@t-online.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
diff --git a/audio/audio.c b/audio/audio.c
index b48471b..d048d26 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -2003,7 +2003,7 @@
         CASE(JACK, jack, Jack);
         CASE(OSS, oss, Oss);
         CASE(PA, pa, Pa);
-        CASE(SDL, sdl, );
+        CASE(SDL, sdl, Sdl);
         CASE(SPICE, spice, );
         CASE(WAV, wav, );