* remove GetModuleHandleA from kernel32.zig. use of A functions
considered harmful.
* make it a compile error to expose WinMain instead of wWinMain. same
thing.
* start code declares wWinMainCRTStartup instead of WinMainCRTStartup
when it has the choice.
* Always allocate an info block per-thread so that libc can store
important stuff there.
* Respect ABI-mandated alignment in more places.
* Nicer code, use slices/pointers instead of raw addresses whenever
possible.
no-frame-pointer-elim and no-frame-pointer-elim-non-leaf have been
deprecated for a while in favour of the newer (and clearer)
frame-pointer attribute.
Starting with LLVM10 the old attributes are silently ignored, leading to
no stack traces in debug mode.
