tested on openbsd, alpine and void

it works on OpenBSD but not on alpine, it requires further tweaks.

this also gives a chance for users to use the default host even if SNI is missing.

the new logging code was crashing if the client didn't support SNI or if required an unknown vhost: this because we short-circuit in handle_handshake to an error, so c->iri isn't populated yet (we don't even read the request). fixes #1

now we log the full IRI requested (before was only the path) and the response line (even for CGI).