ip_auth.c to ip_auth.h. ip_frag_soft_t moves from ip_frag.c to
ip_frag.h. mlfk_ipl.c creates sysctl MIBs that reference control blocks
that are dynamically created when IP Filter is loaded. This necessitated
creating them on-the-fly rather than statically at compile time.
Approved by: glebius (mentor)