postgreSQL: undefined symbol: PQconnectdbParams

Managed to compile and install postgresql under my own account, when running

createdb test

it gave this error: undefined symbol: PQconnectdbParams
the solution is:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path/to/$PGSQL_HOME/lib

where $PGSQL_HOME is the directory that postgresql is installed into.