x86 intrinsics for Multi-Precision Arithmetic

Not a SIMD per se, but still quite important for some use-cases:
- `_addcarry_u32`
- `_addcarry_u64`
- `_addcarryx_u32`
- `_addcarryx_u64`
- `_subborrow_u32`
- `_subborrow_u64`