Fix service name to port resolution
Update README

There's no hope of making it work with BSD make, and GNU make is
in the ports tree anyway.
Bump _XOPEN_SOURCE to 600

Otherwise it's not going to compile on FreeBSD,
because of e.g. missing v/snprintf() and va_copy().
kike: don't use HOST_NAME_MAX

FreeBSD doesn't have it.
Fix infinite loop in the legacy poller
Another fix for the legacy poller