Which reminds me, are there any plans to add SIGWINCH to the set of signals that 's6-svscan -s' can divert?
Maybe, if it's needed. SIGWINCH is not POSIX, and I'd rather not have s6 exhibit different behaviours on systems where it's not supported (same reason why I'm reluctant to add pid namespace support tos6-supervise). If there's a way to make it entirely transparent, why not.
-- Laurent