pgsql and lion : not taking good header at compilation.

Hello,

I'm doing my first steps with postgre, and it seems that the Lion (10.7.4) install of postgre interferes with my install of postgre (9.1.4).

Here's a sample of the program i'm writing:

------------------------------------------------------------------------
int main ()
{

// Params of connection to establish
const char * keywords[] = {"dbname", "user", '\0'};
const char * values[] = {"mydb", "postgresDB", '\0'};

// Check server state
switch (PQpingParams (keywords, values, 0))
{
// some stuff
}
...
}
------------------------------------------------------------------------

Here the error message :
------------------------------------------------------------------------
g++ db_test.o -o db_test -L /usr/local/pgsql/bin -lpq
Undefined symbols for architecture x86_64:
"_PQpingParams", referenced from:
_main in db_test.o
ld: symbol(s) not found for architecture x86_64
------------------------------------------------------------------------

My guess : g++ compile with the "old" version of postgre because if i remove PQpingParams (introduced in 9.1), it compiles.

My question : how to compile with my install of postgre ?

(my install is standard :
./configure
gmake
su
gmake install
)

Many thinks for giving me a hand on this one!
Pierre