ld not usually
affect the generated code, because LLVM can properly optimize the case
where the result is unused.

# Examples

```
use portable_atomic::{AtomicI32, Ordering};

let foo = AtomicI32::new(0b101101);
assert_eq!(foo.fetch_and(0b110011, Ordering::SeqCst), 0b101101);
assert_eq!(foo.load(Ordering::SeqCst), 0b100001);
```