[PATCH] IPv6 transparent proxy support for Squid

Hi,

As NAT support has been included for IPv6 in Linux 3.7 (along with
REDIRECT/DNAT rules), as well as IP6T_SO_ORIGINAL_DST in Linux 3.8, I wrote
a little patch to add support for transparent proxies over IPv6.

It's my first patch for Squid, I hope I've done it correctly :) The patch
is based on the bzr repository.

The only thing I see which can cause trouble is a bug
with linux/netfilter_ipv6/ip6_tables.h on C++ compilers, the bug report and
the patch to fix it are here : https://lkml.org/lkml/2012/9/30/146. It's
only used for the constant IP6T_SO_ORIGINAL_DST. Maybe there is a better
(and clean) way to do so it doesn't force users to update their header
file, but I've haven't found it yet.

Have a nice day,

Alexis