strange buildworld failure

Hi,

I am trying to buildworld but it fails here:
> ===> usr.bin/ypwhich (all)
> cc -O2 -pipe  -std=gnu99 -Qunused-arguments -fstack-protector -Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -
> Wno-pointer-sign -Wno-empty-body -Wno-string-plus-int -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-
> unused-function -Wno-conversion -Wno-switch -Wno-switch-enum -c /usr/src/usr.bin/ypwhich/ypwhich.c
> gzip -cn /usr/src/usr.bin/ypwhich/ypwhich.1 > ypwhich.1.gz
> cc -O2 -pipe  -std=gnu99 -Qunused-arguments -fstack-protector -Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -
> Wno-pointer-sign -Wno-empty-body -Wno-string-plus-int -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-
> unused-function -Wno-conversion -Wno-switch -Wno-switch-enum  -o ypwhich ypwhich.o
> 1 error
> *** [everything] Error code 2
> 1 error
> *** [buildworld] Error code 2
> 1 error

My make.conf has these:
WITHOUT_X11=1
MALLOC_PRODUCTION=1
NO_CLEAN=1

Also, my src.conf had WITHOUT_CLANG but I deleted it and then I
also deleted /usr/obj when it failed for the first time. But that
didn't work. I am building with -j3.

Thanks for any ideas/pointers, Nikos