GCC5/DWARFv5 Handle DW_TAG_atomic_type for C11 _Atomic type qualifier.

GCC5/DWARFv5 Handle DW_TAG_atomic_type for C11 _Atomic type qualifier.

gdb/ChangeLog

	* c-typeprint.c (cp_type_print_method_args): Handle '_Atomic'.
	(c_type_print_modifier): Likewise.
	* dwarf2read.c (read_tag_atomic_type): New function.
	(read_type_die_1): Handle DW_TAG_atomic_type.
	* gdbtypes.c (make_atomic_type): New function.
	(recursive_dump_type): Handle TYPE_ATOMIC.
	* gdbtypes.h (enum type_flag_values): Renumber.
	(enum type_instance_flag_value): Add TYPE_INSTANCE_FLAG_ATOMIC.
	(TYPE_ATOMIC): New macro.
	(make_atomic_type): Declare.

gdb/testsuite/ChangeLog

	* gdb.dwarf2/atomic.c: New file.
	* gdb.dwarf2/atomic-type.exp: Likewise.

include/ChangeLog

	* dwarf2.def: Add DW_TAG_atomic_type.