Commit Briefs
disable -Werror=use-after free for CI
gcc' use after free detection is busted and sees one in vis.c where it's not possible.
use REGRESS_HOST to specify the host to listen to; use in CI
some CI envs don't like `listen on localhost' but tolerate INADDR_ANY or IN6ADDR_ANY_INIT.
enable -Werror on CI
-Wno-deprecated-declarations is needed because of OpenSSL 3 (and macos stupidly deprecating daemon(3) in favour of that trash of posix_spawn.)
add mac_task with disabled runtime tests for the time being
the runtime tests fails on the ci (gg: Connection refused); will be revisited after we get a real `listen on' directive.
add .cirrus.yml
Add a cirrus CI config file that runs the regression suite on linux amd64/aarch64 and on freebsd.