[clang] [compiler-rt] Define signed int overflow with -fms-compatibility (PR #198538)

[Pankaj Chawla via cfe-commits]

pankaj-chawla wrote:

>  We can introduce a runtime check for u<0x7FFFFFD

I think I understood how this effectively proves that wrapround doesn't happen.

https://github.com/llvm/llvm-project/pull/198538