Can not find -lpq

Iam with a problem to compile a C  program that uses
postgres. I am on FreeBSD with Potgsresql installed
in usr/local/pgsql.

any help?

compile messages:


make  all-recursive
Making all in everestserver
Making all in docs
Making all in en
c++  -g -O2  -o everestserver  main.o -lpq
/usr/libexec/elf/ld: cannot find -lpq
*** Error code 1

Stop in /root/rewq/everestserver.
*** Error code 1

Stop in /root/rewq/everestserver.
*** Error code 1

Stop in /root/rewq.
*** Error code 1

Stop in /root/rewq.