Use AL_DIRECT_CHANNELS_SOFT for audio playback.

[foxcpp]

See telegramdesktop/tdesktop#2580.

(cherry picked from commit e3b6e13)

[vyamkovyi]

uhh, sure, this will do the trick but AL_DIRECT_CHANNELS_SOFT was designed quite poorly. The intended use here is to avoid direct channels and play via virtual speakers. As I've also mentioned in comment for the original commit, it must be tested on real 5.1 system before I'd like to see it merged. According to my prediction, front-center and surround channels are going to be dropped.

[crackedmind]

❌ Build kepka 1.0.220-rebbvgqi failed (commit 829e772162 by @john-preston)

[crackedmind]

✅ Build kepka 1.0.220-cpjbqojn completed (commit 829e772162 by @john-preston)

[foxcpp]

https://github.com/openalext/openalext/wiki/AL_SOFT_direct_channels

AL_DIRECT_CHANNELS_SOFT set to AL_TRUE indicates the audio channels are
not virtualized and play directly on the matching output channels if they
exist, otherwise they are dropped. Applies only when playing non-mono
buffers.