* doc/extend.texi (Statement Exprs, Typeof): Discuss __auto_type.
	* ginclude/stdatomic.h (kill_dependency, atomic_store_explicit)
	(atomic_load_explicit, atomic_exchange_explicit)
	(atomic_compare_exchange_strong_explicit)
	(atomic_compare_exchange_weak_explicit): Use __auto_type to
	declare variable initialized with PTR argument.

c-family:
	* c-common.h (enum rid): Add RID_AUTO_TYPE.
	* c-common.c (c_common_reswords): Add __auto_type.
	(keyword_begins_type_specifier): Handle RID_AUTO_TYPE.

c:
	* c-tree.h (c_typespec_keyword): Add cts_auto_type.
	* c-decl.c (declspecs_add_type, finish_declspecs): Handle
	__auto_type.
	* c-parser.c (c_token_starts_typename, c_token_starts_declspecs)
	(c_parser_attribute_any_word, c_parser_objc_selector): Handle
	RID_AUTO_TYPE.
	(c_parser_declspecs): Take argument AUTO_TYPE_OK.
	(c_parser_declaration_or_fndef, c_parser_struct_declaration)
	(c_parser_declarator, c_parser_direct_declarator_inner)
	(c_parser_parameter_declaration, c_parser_type_name): All callers
	changed.
	(c_parser_declaration_or_fndef): Handle declarations with type
	determined from the initializer.

testsuite:
	* gcc.dg/atomic/stdatomic-vm.c, gcc.dg/auto-type-1.c,
	gcc.dg/auto-type-2.c: New tests.

From-SVN: r204731