[Bug libstdc++/54005] Use __atomic_always_lock_free in libstdc++ is_lock_free instead of __atomic_is_lock_free

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54005

--- Comment #35 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Hans-Peter Nilsson from comment #34)
> Can I at least change 
> -         reinterpret_cast<void *>(-__alignof(_M_i)));
> +         reinterpret_cast<void *>(-_S_alignment));
> ?

Yes, OK.