[Portaudio] Compiler warnings for MME, DirectSound, WASAPI

[Dmitry Kostjuchenko]

Hi Ross!

> I agree that the wasapi one looks like it should be investigated (Dmitry?)

Well, I guess Morten is using old sources. That warning in that part
of the code is already silenced. It was just warning without any side
effect on logic. I advise Morten to update to the latest WASAPI
version.

Best regards,
Dmitry.