new to sparc64 -- build problems

[Goodleaf, John M]

Hello,

I'm trying to buildworld (CURRENT) on a Sun Ultra 5. I always hit the
following error, regardless of the cvsup date:

cc -O -pipe -mcpu=ultrasparc -I. -static -DGENERATOR_FILE
-DTARGET_CPU_DEFAULT=TARGET_CPU_ultrasparc -DIN_GCC -DHAVE_CONFIG_H
-DPREFIX=\"/usr\"
-I/usr/obj/usr/src/gnu/usr.bin/cc/cc_tools/../cc_tools
-I/usr/src/gnu/usr.bin/cc/cc_tools/../cc_tools
-I/usr/src/gnu/usr.bin/cc/cc_tools/../../../../contrib/gcc
-I/usr/src/gnu/usr.bin/cc/cc_tools/../../../../contrib/gcc/config 
-I/usr/obj/usr/src/sparc64/legacy/usr/include -c
/usr/src/gnu/usr.bin/cc/cc_tools/../../../../contrib/gcc/gencheck.c
In file included from hconfig.h:1,
                 from /usr/src/contrib/gcc/gencheck.c:21:
/usr/src/gnu/usr.bin/cc/cc_tools/auto-host.h:320:2: #error "I don't
know what arch this is."
*** Error code 1

Stop in /usr/src/gnu/usr.bin/cc/cc_tools.
*** Error code 1

I've tried setting the __sparc64__ and defining environment
variables like MACHINE_ARCH, but it just doesn't work. Is this
covered somewhere in some documentation I've not seen?

Thanks,
John