can not configure in centos 6 x64

In centos 6.2 x64 with postgresql 9.1.4 x64 when I try to ./configure  psqlodbc-09.01.0100

I get this error :

PQconnectdb in -lpq... no
configure: error: libpq library not found

I think libpq has currently installed.


i currenly install :
 groupinstall "Development Tools"
 postgresql91 postgresql91-devel postgresql91-server postgresql91-libs postgresql91-contrib


I also send this problem at http://postgresql.1045698.n5.nabble.com/can-not-configure-in-centos-6-x64-td5713062.html


THX