Re: IPv6 Support for INET/CIDR types.

> I don't believe the original patch ever made it into anything.

vadim's original patch was the basis for BIND's ipv6 support in the
set of functions that pgsql borrows from BIND.  so, it did make it
into _something_ just not the modified pgsql mirrors of these functions.

my proposal is that we do away with the modified pgsql mirrors of these
functions and teach the INET and CIDR handlers to "wrap" the BIND functions
in a way that modifies the presentation format to be postgres-compatible.
that way postgres can import new versions of, or use LIBC versions of,
the BIND functions without having to worry about local modifications to them.