atomic_base.h: Use __always_inline__ instead of always_inline.

atomic_base.h: Use __always_inline__ instead of always_inline.

	* include/bits/atomic_base.h: Use __always_inline__ instead of
	always_inline.
	* include/bits/atomic_futex.h: Likewise.
	* include/bits/c++config: Use __abi_tag__ instead of abi_tag.
	* include/ext/pb_ds/detail/gp_hash_table_map_/gp_ht_map_.hpp: Use
	__packed__ instead of packed.
	* include/std/shared_mutex: Use __unused__ instead of unused.
	* testsuite/17_intro/headers/c++1998/all_attributes.cc: New.
	* testsuite/17_intro/headers/c++200x/all_attributes.cc: New.
	* testsuite/17_intro/headers/c++2014/all_attributes.cc: New.

From-SVN: r220243