libstdc++/5037
* config/cpu/sparc/sparc32/bits/atomicity.h
(struct __Atomicity_lock<__inst>): Add.
(__Atomicity_lock<__inst>::_S_atomicity_lock): Add.
(__exchange_and_add): Use __Atomicity_lock<0>::_S_atomicity_lock
instead of lock local to static function.
(__atomic_add): Likewise.
Co-Authored-By: Loren J. Rittle <ljrittle@acm.org>
From-SVN: r47782