Public issue https://github.com/mackron/miniaudio/issues/582

Checking for __ORBIS__ and __PROSPERO__ first avoid identifying PS4/PS5 as BSD systems.

In a stereo scenario, the listener will use a channel map of
{SIDE_LEFT, SIDE_RIGHT}, but sounds will default to
{FRONT_LEFT, FRONT_RIGHT}. As a result, channel mapping will be
performed to do the conversion. By instead defaulting stereo sounds
to be consistent with the listener, a passthrough path can be used
instead, improving efficiency.

fixed a little problem with changing devices when initialized our device config as duplex; fixed typos

The idea behind this is to avoid subtle bugs that are a result of
accidentally not using atomic operations to reference variables that
must always be used atomically.

This commit does not convert every atomic variable to the new system,
however going forward this will need to be adopted over time.

Public issue https://github.com/mackron/miniaudio/issues/572