MFC r242079:

MFC r242079:
  Remove the IPFIREWALL_FORWARD kernel option and make possible to turn
  on the related functionality in the runtime via the sysctl variable
  net.pfil.forward. It is turned off by default.

MFC r242082:
  Note the removal of the IPFIREWALL_FORWARD kernel option.

MFC r242463:
  Remove the recently added sysctl variable net.pfil.forward.
  Instead, add protocol specific mbuf flags M_IP_NEXTHOP and
  M_IP6_NEXTHOP. Use them to indicate that the mbuf's chain
  contains the PACKET_TAG_IPFORWARD tag. And do a tag lookup
  only when this flag is set.

git-svn-id: svn://svn.freebsd.org/base/stable/9@243586 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f