I am very comfortable in saying both John and I are done with SRFI 170, and it only exposes a not very controversial bit of SRFI 198, syscall-error? to determine if an object is one, and the accessors for its components. I'm pretty sure there's nothing that can conceivably be added to this object now that syscall-name is in it. The design space is rather finite. in part thanks to the memory and I/O limitations (slow 110/300 baud terminals) of the systems Original Formula UNIX ran on.
I have no informed opinion on SRFI 198, pretty sure I'll be finished with my part by the end of the week if not today, but given that it's summer, 60 days, or even the end of October to get past the crush of the beginning of the academic year would not be out of the question.