Fix: handle NULL node in getaddrinfo

Signed-off-by: David Goulet <dgoulet@ev0ke.net>
Add option to allow inbound connections

This adds the possibility of telling torsocks to allow inbound
connections meaning allowing listen() and accept()/accept4() for non
localhost address.

Add a AllowInbound 0|1 option to the configuration file along with a
TORSOCKS_ALLOW_INBOUND environment variable to control that behavior.

By default, Unix socket are allowed.

Signed-off-by: David Goulet <dgoulet@ev0ke.net>
Fix: add torsocks.conf option type

Signed-off-by: David Goulet <dgoulet@ev0ke.net>