re PR libstdc++/60940 (general operations on atomic types do not work with atomic integral typedefs)

	PR libstdc++/60940
	* include/bits/atomic_base.h: Remove atomic integral typedefs as
	synonyms for __atomic_base<int> etc.
	* include/std/atomic: Make atomic_int a synonym for atomic<int> and
	likewise for all atomic integral types.
	* testsuite/29_atomics/atomic_integral/cons/copy_list.cc: New.
	* testsuite/29_atomics/atomic/60695.cc: Adjust dg-error line number.

From-SVN: r219790