I'm now trying to update on a second system. I'm using the suggested:

    /usr/src# export CVS_RSH=ssh
    /usr/src# cvs -d anoncvs@anoncvs.netbsd.org:/cvsroot update -Pd -r 
netbsd-1-6 libexec/talkd

That seems to get the files from CVS just fine. However, after a cd 
to libexec/talkd:

# make cleandir dependall
rm -f talkd.o announce.o process.o table.o print.o  talkd.ln 
announce.ln process.ln table.ln print.ln
rm -f a.out [Ee]rrs mklog core *.core ntalkd
rm -f talkd.cat8
rm -f .depend /usr/src/libexec/talkd/tags
CC=/usr/src/tools/tools.NetBSD-1.6-i386/bin/i386--netbsdelf-gcc 
/usr/src/tools/tools.NetBSD-1.6-i386/bin/nbmkdep -a  -nostdinc 
-isystem /usr/include  talkd.c announce.c process.c table.c print.c
/usr/src/tools/tools.NetBSD-1.6-i386/bin/nbmkdep: not found
*** Error code 127

Stop.
make: stopped in /usr/src/libexec/talkd
#

What might I be doing wrong? This is kind of weird because it worked 
fine on another 1.6 system.