[compiler-rt] [compiler-rt] Work around incompatible Windows definitions of (S)SIZE_T (PR #106311)

[Mariusz Borsa via llvm-commits]

wrotki wrote:

My clang command line has  `-arch arm64 -arch i386 -arch x86_64` , while I only see `-arch arm64 -arch x86_64` in open source build, which is probably why it works there, only 64 bit.

Let me experiment with your suggestions, thanks!

https://github.com/llvm/llvm-project/pull/106311