On Thu Jul 16 21:42:02 2015, vladv@rvtn.org wrote:
> I do not know the consequences of always setting sin6_scope_id
> on the operation of dhclient or dhcpd, nor have I tested it on systems
> other than OpenBSD.

=> as an IPv6 implementor I can answer: usually setting
the sin6_scope_id when it is not required does nothing
(i.e., it is ignored). Nevertheless I recommend to add
an #ifndef around the if so the current behavior can be switched
from the site.h header (#ifndef to get sin6_scope_id in all
cases by default).