Enable Windows Arm64 support

[alinpahontu2912]

Added checks to make use of the available libsndfile.dll for windows on arm64.
Numpy and cffi can be pip installed on arm64, so this should be available too.
Needed for torchaudio support on WinArm64

[bastibe]

Neither numpy nor cffi are available for Windows arm64. Also, Python x64 on arm64 reports being arm64, so this change would break the x64 installation.

[alinpahontu2912]

Hey, just to clarify—when you say numpy and cffi aren’t available on Windows ARM64, do you mean they don’t have their own ARM64 distributions on PyPI? Also, I’m a bit confused about the Python x64 on ARM64 reporting as ARM64—could you elaborate on how that would break the x64 installation? I tested building the package on both ARM64 and x64, and it seemed to work fine.

[bastibe]

I have an ARM64 Windows machine, with python installed in both an ARM64 version, and an AMD64 version. Numpy wheels are only available for install in the AMD64 version. The ARM64 version tries to install numpy.tar.gz, which fails, of course.

If you run python AMD64 on an ARM64 device, it will report that platform.machine() is 'ARM64'. Therefore, it is not possible to use platform.machine to differenciate between and emulated AMD64 binary running on ARM64, and a native ARM64 binary; Both report as ARM64.

[alinpahontu2912]

Oh I understand now, thanks for the clarification! Just a quick note—if you have Visual Studio with MSVC installed, the numpy package works on ARM64 too, it will build successfully in that setup.

[bastibe]

Good to know, thank you!

I will hold off on publishing Windows/ARM64 soundfile until both cffi and numpy are available for the platform. However, I also don't know yet how it would even work, given the above platform.machine confusion. If you'd like to contribute or discuss a possible solution, I'd be happy to merge that.

[Greenie0701]

@bastibe & @alinpahontu2912 I guess, right now we have both cffi and numpy being released for Windows ARM, this PR can be considered for review now

[bastibe]

That's wonderful news! Is this pull request ready to merge?