Unable to compile Bro on Solaris 11 Express.

I was unable to compile Bro-1.5.1 on Solaris 11 Express.Below are the
last lines of warnings make gave me.
./configure did not show any problem.

gcc -g -O2 -I/include -I/usr/include -o hf hf.o setsignal.o
version.o -lreadline -lz -lpcap -lpcap -lssl -lcrypto -lnsl
-lsocket -lpcap -ltermcap
Undefined first referenced
symbol in file
_res hf.o
ld: fatal: symbol referencing errors. No output written to hf
collect2: ld returned 1 exit status
make[4]: *** [hf] Error 1
make[4]: Leaving directory `/home/abar/bro-1.5.1/aux/hf'
make[3]: *** [all-recursive] Error 1
make[3]: Leaving directory `/home/abar/bro-1.5.1/aux'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/home/abar/bro-1.5.1/aux'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/abar/bro-1.5.1'
make: *** [all] Error 2