IPv6 support for rblsmtpd

Needs a tcpserver with IPv6 support that set TCP6 env variable.

This is a patch against rblsmtpd.c that bypasses the DNSBL checks if the connection is IPv6 based.

This is simply due to the fact that there are currently no IPv6 enabled DNSBLs and looking up an IPv6 address has not been specified.

In the future the patch could be changed to reverse the IPv6 address in the nibble format used for ip6.arpa. lookups.
http://gurubert.de/qmail/rblsmtpd/message-ip

This is a patch against rblsmtpd from ucspi-tcp 0.88 that allows to set a $RBLMESSAGE environment variable (e.g. in /etc/tcp.smtp).

The content of the variable will be prepended to the string that is returned by querying the various DNSBLs.

This can be used e.g. to add contact info to the SMTP error message the sender receives.

The patch also replaces %IP% in the DNSBL return string with the value of $TCPREMOTEIP. Some DNSBLs do return an URL with %IP% as a placeholder.
Merge branch 'rblsmtpd-verbose'