Public issue https://github.com/mackron/miniaudio/issues/484

Public issue https://github.com/mackron/miniaudio/issues/484

Public issue https://github.com/mackron/miniaudio/issues/484

Public issue https://github.com/mackron/miniaudio/issues/533

Public issue https://github.com/mackron/miniaudio/issues/532

When there are no capture nor playback devices, pContext->pDeviceInfos
is NULL and pContext->playbackDeviceInfoCount is 0.
Unfortunately, any arithmetic on NULL is UB, including trivial +0,
which triggers UB sanitizer. This can lead to crashes,
for example when compiling with Zig, which enables UBsan by default.

Public issue https://github.com/mackron/miniaudio/issues/527

This is being forced when ma_ios_session_category_default is specified.

Public issue https://github.com/mackron/miniaudio/issues/506

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

We already map the in:out 1:1 mappings above the switch statement, but
the code for "simple" mapping stomps on the mappings.

Also, even before that loop was added, mix mode "simple" did not
necessarily map to the same channel types you'd expect. For example, if
you have a 6-channel input and 8-channel output, you would get something
like this with "simple":

  Correct:  CHANNEL_FRONT_LEFT -> CHANNEL_FRONT_LEFT
  Correct:  CHANNEL_FRONT_RIGHT -> CHANNEL_FRONT_RIGHT
  Correct:  CHANNEL_FRONT_CENTER -> CHANNEL_FRONT_CENTER
  Correct:  CHANNEL_LFE -> CHANNEL_LFE
  Wrong:    CHANNEL_SIDE_LEFT -> CHANNEL_BACK_LEFT
  Wrong:    CHANNEL_SIDE_RIGHT -> CHANNEL_BACK_RIGHT

Instead of just assuming the input channel map is a truncation of the
output channel map and has channels in the same order, just keep the
existing 1:1 mappings and hope that's sufficient.
Signed-off-by: Steven Noonan <steven@uplinklabs.net>