c2ffi handling va_list

one of the cffi/TODO items has -> Handle va_list. For now it's treated as any other argument. Maybe someone has thought deeply about how to do this? Please let me know if you have any suggestions. [It seems borodust/claw tries to handle this by converting va_list args to variadic lisp arguments - but it still seems to blow up at a cffi:parse-type. Or maybe it is a defect with my Clang-7.0 stdarg vs. what is included with gcc]