problem smp w/ crafty chess engine

Can anyone help with this, I am trying to get my dual amd mp system to compile 
crafty so that it can use the smp features, but I am having no luck :(

This is the target that is in the make file:

freebsd:
	$(MAKE) target=FreeBSD \
		CC=gcc CXX='$(CC)' \
		CFLAGS='$(CFLAGS) -fomit-frame-pointer -mcpu=i686 -O3 -Wall' \
		CXFLAGS=$(CFLAGS) \
		LDFLAGS=$(LDFLAGS) \
		opt='$(opt) \
		     -DUSE_ASSEMBLY -DFAST -DPOSIX -DSMP -DCPUS=2' \
		asm=X86.o \
		crafty-make


This is final output

gcc -fomit-frame-pointer -mcpu=i686 -O3 -Wall -DUSE_ASSEMBLY -DFAST -DPOSIX 
-DSMP -DCPUS=2 -DFreeBSD -c bench.c
cc -c  -DUSE_ASSEMBLY -DFAST -DPOSIX -DSMP -DCPUS=2 -DFreeBSD egtb.cpp
egtb.cpp:3795: warning: `TB_CRC_CHECK' initialized and declared `extern'
gcc -fomit-frame-pointer -mcpu=i686 -O3 -Wall -DUSE_ASSEMBLY -DFAST -DPOSIX 
-DSMP -DCPUS=2 -DFreeBSD -c dgt.c
as  -o X86.o X86.s
gcc  -o crafty searchr.o search.o singular.o thread.o searchmp.o repeat.o 
next.o nexte.o nextr.o history.o quiesce.o evaluate.o movgen.o make.o 
unmake.o hash.o attacks.o swap.o boolean.o utility.o valid.o probe.o book.o 
data.o drawn.o edit.o epd.o epdglue.o init.o input.o interupt.o iterate.o 
main.o option.o output.o phase.o ponder.o preeval.o resign.o root.o learn.o 
setboard.o test.o testepd.o time.o validate.o annotate.o analyze.o evtest.o 
bench.o egtb.o dgt.o -lstdc++ -lpthread X86.o -lm
/usr/bin/ld: cannot find -lpthread
gmake[3]: *** [crafty] Error 1
gmake[3]: Leaving directory `/usr/home/eriq/Crafty'
gmake[2]: *** [crafty-make] Error 2
gmake[2]: Leaving directory `/usr/home/eriq/Crafty'
gmake[1]: *** [freebsd] Error 2
gmake[1]: Leaving directory `/usr/home/eriq/Crafty'
gmake: *** [default] Error 2
{eriq_at_merlin} ~/Crafty>