Builds on 64-bit linux. DNS black/white list support. Manpage extensively debugged.

Now builds on 64-bit linux. Now can blacklist or whitelist hosts by looking up in a DNS list (like zen.spamhaus.org. DNS lists work by looking up a fake hostname made up of the reversed-quads of an IP address, and the domain name of the list. So to lookup 192.168.55.10 at zen.spamhaus.org we'd query 10.55.168.192.xen.spamhaus.org. If we get back an IP address for this nonsense hostname, then it means the IP 192.168.55.10 is in the list, and pam_ihosts can either reject a host from logging in, or allow login to continue, on the basis of this information. Manpage has been fixed to work with more terminal types.