Enable ASIO support in MSVC builds

[messmerd]

Last week I added support for building PortAudio with ASIO to vcpkg, and now I'm enabling it here.

Only our Windows MSVC builds use vcpkg at the moment, so it will only be enabled there. However, with #8218 the MinGW builds will also support it. Unfortunately the Windows ARM64 builds use the MSYS2 PortAudio package which does not have ASIO support yet.

Progress towards #1173

TODO:

• Fix input/output device selection (upstream bug?)
• Licensing concerns? (GPLv3 library in a GPLv2+ application)

[messmerd]

Just did a little testing, and it sounds very choppy and clearly broken when using the ASIO backend. I wonder if #7444 would help? @sakertooth

[sakertooth]

Just did a little testing, and it sounds very choppy and clearly broken when using the ASIO backend. I wonder if #7444 would help? @sakertooth

Will do some testing and get back to you.

[sakertooth]

Hi @messmerd

Can confirm that ASIO is crackling, as well as practically everything else on Windows (tested via WINE). ChatGPT pointed me to some logic errors in my code (most importantly in the audio callback), so I'm hoping the crackling is fixed with those issues addressed. Will test again.

[messmerd]

Unfortunately PortAudio with the ASIO backend fails to initialize:

The input and output devices are not selectable for some reason.

[sakertooth]

Yeah, WDM-KS has the same issue where there are just no devices in the combo boxes. I don't know if you have to do some preliminary setup (like installing ASIO4ALL for example or something).