cpphash.c (is__va_args__): New function.

	* cpphash.c (is__va_args__): New function.
	(count_params): Fix line reported in error messages.  Use
	is__va_args__.  Don't return ')' on error.  Flag GNU style
	rest args macro definitions.
	(parse_define): Check macro name is not __VA_ARGS__.
	(save_expansion): Check identifier in non-varargs-macro is
	not __VA_ARGS__.  Don't flag GNU_VARARGS.
	* cpplex.c (parse_args): Accept no argument iff GNU_REST_ARGS.
	(maybe_paste_with_next): Use per-macro GNU_REST_ARGS rather
	 than per-token GNU_VARARGS.
	* cpplib.h (GNU_VARARGS): Remove.
	(GNU_REST_ARGS): New.

	* gcc.dg/cpp/macsyntx.c: New tests.

From-SVN: r34919