re PR libstdc++/65033 (C++11 atomics: is_lock_free result does not always match the real lock-free property)

PR libstdc++/65033

 * include/bits/atomic_base.h (__atomic_base<T>::is_lock_free): Build
 a fake pointer indicating type alignment.
 (__atomic_base<T *>::is_lock_free): Likewise.
 * include/std/atomic (atomic<T>::is_lock_free): Likewise.

From-SVN: r221701