A variable that specifies an audio backend to use.
Defined in <SDL3/SDL_hints.h>
By default, SDL will try all available audio backends in a reasonable order until it finds one that can work, but this hint allows the app or user to force a specific driver, such as "pipewire" if, say, you are on PulseAudio but want to try talking to the lower level instead.
This hint should be set before SDL is initialized.
This hint is available since SDL 3.0.0.