[reSIProcate] Ares support for using IPv6 DNS servers

[Rohan Mahy <rohan@xxxxxxxxx>]

Hi,

I made some changes to ares to move us toward being able to use v6 DNS 
servers.

1. I added the a family identifier and room for v6 server addresses to 
the server_state data structure in
        ares_private.h

2. I also changed the open_udp_socket and open_tcp_socket functions in:
        ares_process.c
so IPv6 capable systems can connect to a mixture of IPv4 and IPv6 DNS 
servers.

What else needs to be done?

-  the ares_init routines which populate the channel and server_state 
data structures need to be modified to insert IPv6 DNS servers and set 
the family for every server.  There are about 5 places where this needs 
to be mucked with.
-  it would be very nice if ./configure would detect IPv6 libraries on 
the system and set the right flag in the ares Makefile automagically.

thanks,
-rohan