Block IPv6 packets in pf(4) that have hop-by-hop options header or
destination options header. Such packets can be passed by adding
"allow-opts" to the rule. So IPv6 options are handled like their
counterpart in IPv4 now.
tested by benno@; OK henning@
Obtained from: OpenBSD, bluhm <bluhm@openbsd.org>, c50c83ac27
Sponsored by: Rubicon Communications, LLC ("Netgate")