makes a new accept() socket have the nonblock behavior.
makes a new accept() socket have the nonblock behavior.

slightly modified version from the original diff by theo, based
on comments by niels@ and deraadt@; both ok'ed.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars