NanoBSD Build Failure

[Thomas D. Dean]

I am attempting to rebuild nanoBSD on an AMD64 system, using the same 
config file I used a couple years ago on a 32-bit system.

The target system is a TS5700 with an AMD Elan SC520, currently running 
nanoBSD from FreeBSD 6.2-PRERELEASE #0: Sun Oct 15 16:25:50 PDT 2006.

 From dmesg:
CPU: AMD Enhanced Am486DX4/Am5x86 Write-Back (486-class CPU)
   Origin = "AuthenticAMD"  Id = 0x494  Stepping = 4
   Features=0x1<FPU>

The buildworld part finished Ok.  The gcc arguments seem OK for a 32-bit 
system.

Buildkernel fails:

--------------------------------------------------------------
 >>> Kernel build for MYKERNEL started on Sun May 20 19:36:28 PDT 2012
--------------------------------------------------------------
===> MYKERNEL
mkdir -p /usr/obj/nanobsd.TS5700//usr/src/sys
--------------------------------------------------------------
 >>> stage 1: configuring the kernel
--------------------------------------------------------------
cd /usr/src/sys/amd64/conf; 
PATH=/usr/obj/nanobsd.TS5700//usr/src/tmp/legacy/usr/sbin:/usr/obj/nanobsd.TS5700//usr/src/tmp/legacy/usr/bin:/usr/obj/nanobsd.TS5700//usr/src/tmp/legacy/usr/games:/usr/obj/nanobsd.TS5700//usr/src/tmp/usr/sbin:/usr/obj/nanobsd.TS5700//usr/src/tmp/usr/bin:/usr/obj/nanobsd.TS5700//usr/src/tmp/usr/games:/sbin:/bin:/usr/sbin:/usr/bin 
  config  -d /usr/obj/nanobsd.TS5700//usr/src/sys/MYKERNEL 
/usr/home/tomdean/nanoBSD/MYKERNEL
/usr/home/tomdean/nanoBSD/MYKERNEL: unknown option "I486_CPU"
*** Error code 1
1 error
*** Error code 2
1 error


Any ideas?

Tom Dean