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

[Alexander Richardson via llvm-commits]

arichardson wrote:

The other option would be 

```
#if SANITIZER_APPLE && SANITIZER_WORDSIZE == 32
typedef int    PTRDIFF_T;
#else
typedef __sanitizer::sptr    PTRDIFF_T;
#endif
```

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