Remove windows.h depend on Win32 platform

[windowsair]

This patch removes the windows.h header to avoid namespace pollution and improve compilation speed.

For GCC/Clang, a minimal part of the Windows headers is still included. I intend to further remove their dependencies. If the ABI is stable, access to the PEXCEPTION_POINTERS ExceptionInfo member can be directly achieved through pointer arithmetic.

Looking forward to your reply :)

[windowsair]

Hello, it looks like the CI task failed early. If possible, I can submit a new PR to fix the CI issue first.

[nihui]

Thanks for your contribution !