Okay, the issue is specifically with net/tnftp, which is built as part
of bootstrapping pkgsrc on Darwin/MacOS X (at least).  The configure
step is somehow not picking up the fact that MacOS X 10.3.9 has a
'dirname()' function.

I've worked around it by hacking the "net/tnftp/files/config.h.in"
file to explicitly:

   #define HAVE_DIRNAME 1

so it will persist when bootstrap/work/tnftp/config.h is created.

With this hack in place, the bootstrap operation completes with no
further problems.

-- 
John D. Baker, KN5UKS                    NetBSD     Darwin/MacOS X
jdbaker(at)mylinuxisp(dot)com                 OpenBSD            FreeBSD
BSD -- It just sits there and _works_!