dhcpcd-5.99.5 final testing for DHCPv6

[Roy Marples <roy%marples.name@localhost>]

Hi Everyone

I've finally found the time to finish DHCPv6 support in dhcpcd :D
The only biggie I've not entirely finished is DAD support. In a 
nutshell, no kernel (either Linux or BSD) will allow userland to send 
from the unspecified address, which means we HAVE to use the kernel for 
RFC conformant DAD support which only works when adding tentative 
addresses. This isn't great and as such we just log DAD failures - this 
is no better or worse than other implementations.
Future work will try and work around this so we can send a DHCP6 
DECLINE message when duplicates are found.

A side effect of this is that we run our hook script when addresses may 
be in the tentative state.
This *may* be fixed before dhcpcd-6.0.0 is finally released.

The only thing I intend to do before release is add a rtadvd(8) hook 
script for better Prefix Delegation support:
http://roy.marples.name/projects/dhcpcd/ticket/262

The new code has extensively been tested under valgrind(1) and has been 
working well for me now for many months.

This is your final time to test it before release. Grab your tarball 
from here:
ftp://roy.marples.name/pub/dhcpcd/dhcpcd-5.99.5.tar.bz2

Thanks,

Roy