The ifdef name was a big clue! "SIGHAND" is short for signal handler. Sure, there is an implicit connection here from "signal handler" to "all code must be as

The ifdef name was a big clue! "SIGHAND" is short for signal handler. Sure, there is an implicit connection here from "signal handler" to "all code must be async signal safe," but that association is pretty well known to most openssh authors and code reviewers. Oh well, mistakes happen.