Variable Length Arrays not supported by MSVC.

[sizeak]

Hi, I'm not sure if it's something you want to support, but you can't currently build this with MSVC (Visual Studio). "I don't plan to support MSVC." is a perfectly reasonable response IMO, so no pressure! I don't usually build for Windows, but the Conan CI builds for it by default, so I've been testing with VS 2019.

It seems that they don't support VLAs since they were made optional in C11, and have no plans to ever support them:
https://devblogs.microsoft.com/cppblog/c11-and-c17-standard-support-arriving-in-msvc/#variable-length-arrays

I suppose to support MSVC the VLAs would need replacing with good old malloc. WDYT?

[larsbs]

@simoncent If the only change we have to do is replacing the VLAs, I don't mind. However, currently I don't have the time to doing so (and I don't remember exactly where I could've used them, since I tend to prefer "good ol' malloc".