Zig tracking issue

[dweiller]

This is a list of Zig issues affecting zimalloc development:

• cannot cross compile linux -> windows with an extern declaration for VirtualAlloc2, likely due to the included mingw not exporting it in the .def files other than for arm32. The latest mingw release does not include VirtualAlloc2 in .def files for other platforms but a recent patch to mingw-w64 does include it.
• struct sizes > 2 ^ 31 cause problems and require workarounds; wanting structs of this size might just be a niche use-case that isn't going to be supported (see crash with struct size exceeding u32 ziglang/zig#17664 for upstream issue).