https://gcc.gnu.org/ml/gcc-patches/2018-08/msg00977.html
	libcpp/
	* internal.h (_cpp_save_parameter): Take parmno, not macro.
	(_cpp_unsave_parameters): Declare.
	* macro.c (_cpp_save_parameter): Take parm number, not macro.
	Return true on success.
	(_cpp_unsave_parameters): New.
	(parse_params): Take parm_no and variadic pointers, not macro.
	Reimplement parsing logic.
	(create_iso_definition): Adjust parse_params changes.  Call
	_cpp_unsave_parameters here.
	(_cpp_create_definition): Don't unsave params here.
	* traditional.c (scan_parameters): Take n_param pointer, adjust.
	(_cpp_create_trad_definition): Ajust scan_parameters change.  Call
	_cpp_unsave_parameters.
	gcc/testsuite/
	* gcc.dg/cpp/macsyntx.c: Adjust expected errors.
	* gcc.dg/cpp/macsyntx2.c: likewise.

From-SVN: r263600