* net: allow close() to ignore SSL failures due to disconnections
Comes with this PR is also a SIGPIPE handling contraption.
* net: don't do selectSigpipe() on macOS
macOS sockets have SO_NOSIGPIPE set, so an EPIPE doesn't necessary mean
that a SIGPIPE happened.
* net: fix alreadyBlocked logic
* net: WSAESHUTDOWN is also a disconnection error