[ns] nam build fails (cannot find -lnsl) on FreeBSD 4.4

[Shill <fake@verizon.net>]

$ uname -a
FreeBSD cabernet.cs.ucla.edu 4.4-RELEASE FreeBSD 4.4-RELEASE #0: Wed Oct
10 13:03:42 PDT 2001    
root@cabernet.cs.ucla.edu:/usr/src/sys/compile/SMP  i386

The problem has already been documented:
http://www.isi.edu/nsnam/archive/ns-users/webarch/current/msg02326.html

I was trying to build nam as part of the ns-allinone-2.1b8 distribution.

c++   -o nam  tkcompat.o tkUnixInit.o xwd.o netview.o netmodel.o edge.o
packet.o node.o main.o  trace.o queue.o drop.o animation.o agent.o
feature.o  route.o transform.o paint.o state.o monitor.o anetmodel.o 
random.o rng.o view.o graphview.o netgraph.o tracehook.o lan.o psview.o
group.o editview.o tag.o address.o animator.o  wnetmodel.o nam_stream.o
enetmodel.o testview.o parser.o  trafficsource.o gen/version.o
gen/nam_tcl.o  -L/home/abalk/ns-allinone-2.1b8/tclcl-1.0b11 -ltclcl
-L/home/abalk/ns-allinone-2.1b8/otcl-1.0a7 -lotcl
-L/home/abalk/ns-allinone-2.1b8/lib -ltk8.3
-L/home/abalk/ns-allinone-2.1b8/lib -ltcl8.3
-L/home/abalk/ns-allinone-2.1b8/zlib-1.1.3 -lz  -L/usr/X11R6/lib -lXext
-lX11  -lnsl -lm
/usr/libexec/elf/ld: cannot find -lnsl
*** Error code 1

Stop in /home/abalk/ns-allinone-2.1b8/nam-1.0a10.

Does anybody know what's wrong? Is a fix available?

Shill