problems with 'make buildworld' on current

[Landon Stewart]

When I do a "make buildworld" I get an error about an incomplete type for field 'inc4_route'.  I've read the /usr/src/UPDATING and found no real references to this type of problem.

Am I jumping too far between 4.3-REL and current?
Do I need some compile options? 
Do I need the compat4.x.i386 installed?
Any other ideas?

# uname -a

FreeBSD pirahna.awe-full.com 4.3-RELEASE FreeBSD 4.3-RELEASE #0: Sat Apr 21 10:54:49 GMT 2001     [EMAIL PROTECTED]:/usr/src/sys/compile/GENERIC  i386

===> usr.bin/systat

cc -nostdinc -O -pipe     -I/usr/obj/usr/src/i386/usr/include  -c /usr/src/usr.bin/systat/cmds.c

... <snip> ...

cc -nostdinc -O -pipe     -I/usr/obj/usr/src/i386/usr/include  -c /usr/src/usr.bin/systat/tcp.c

In file included from /usr/obj/usr/src/i386/usr/include/netinet/tcp_var.h:40,

                 from /usr/src/usr.bin/systat/tcp.c:56:

/usr/obj/usr/src/i386/usr/include/netinet/in_pcb.h:106: field `inc4_route' has incomplete type

*** Error code 1

4 error codes follow this one, all the same, and then a "stop in /usr/src".