We get the server IP as seen from the client side using the ssh
ProxyCommand option, and as seen from the server side using the
SSH_CONNECTION environment variable.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

• Quote all macro arguments.
• Switch deprecated uses of AM_INIT_AUTOMAKE and AC_OUTPUT to the
  preferred forms.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

Signed-off-by: Anders Kaseorg <andersk@mit.edu>