Merge changes I6b304dfb,I4a3c2035,I5af12b3f,I0ef33ca6,I149c46e7
* changes:
Add icmp6.h and ip6.h files from current NetBSD libc.
Include the Linux ipv6.h header from netinet/in.h, to get things like in6_pktinfo.
Add IN6ADDR_LOOPBACK_INIT macro to <netinet/in6.h>, as the kernel headers do not provide it anymore.
Update IPv6 kernel headers with new 2.6.37 headers, cleaned by update_all.py. (It wanted to do many other changes, most of them cosmetic, but I only included the IPv6 changes.)
Fix syntax error in defaults.py.