https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88270
--- Comment #5 from Eric Blake <eblake at redhat dot com> --- For what it's worth, POSIX requires syslog() to support %m, and this is the case even on BSD systems. So a new __attribute__((format(syslog, x, y))) archetype would be an easy way of at least notating functions where %m must be portable, even when flagging %m for printf.
