d: Merge upstream dmd b0df0e982

d: Merge upstream dmd b0df0e982

Adds a struct ParameterList to encapulate parameter and vararg
information in the front-end.

Reviewed-on: https://github.com/dlang/dmd/pull/11226

gcc/d/ChangeLog:

	* dmd/MERGE: Merge upstream dmd b0df0e982.
	* d-builtins.cc (build_frontend_type): Use VarArg for varargs_p.
	* d-codegen.cc (declaration_type): Call TypeFunction::create with
	argument VARARGnone.
	(parameter_type): Likewise.
	(d_build_call): Use new field names and member functions.
	* d-target.cc (Target::cppParameterType): Call TypeFunction::create
	with argument VARARGnone.
	* types.cc (TypeVisitor::visit (TypeFunction *): Use new field names
	and member functions.