Data sources always empty on macOS Catalina

[Frederik Seiffert]

On macOS Catalina (and possibly earlier macOS releases), getting `AudioDevicePropertyDataSources` always returns the error kAudioHardwareUnknownPropertyError (2003332927) in `copyProperty:forChannel:datasize:ptr:`.

Any idea what might be going on here? Is the code in this project no longer supported in recent macOS releases?