d: Fix internal compiler error: in d_init_builtins, at d/d-builtins.cc:1121

d: Fix internal compiler error: in d_init_builtins, at d/d-builtins.cc:1121

gcc/d/ChangeLog:

	PR d/90444
	* d-builtins.cc (build_frontend_type): Build anonymous RECORD_TYPE
	nodes as well, push all fields to the struct members.
	(d_build_builtins_module): Push anonymous va_list structs to the
	builtins module, naming them __builtin_va_list.
	(d_init_builtins): Use sorry instead of gcc_unreachable if va_list did
	not succeed in being represented as a D type.

From-SVN: r274765