Revert "ecpg: Don't link compatlib with libpq"
Revert "ecpg: Don't link compatlib with libpq"

This reverts commit 3780fc679cc428c1f211e1728c4281ca15e9746b.

HP-UX didn't like it.  There would probably be a way to fix that, but
since the net effect of all of this is zero because ecpg ends up using
libpq anyway, it's not worth bothering further.

greenplum-db/gpdb,ovr/postgres-xl,techdragon/Postgres-XL,50wu/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,adam8157/gpdb,pavanvd/postgres-xl,jmcatamney/gpdb,adam8157/gpdb,xinzweb/gpdb,xinzweb/gpdb,ovr/postgres-xl,pavanvd/postgres-xl,xinzweb/gpdb,50wu/gpdb,lisakowen/gpdb,yazun/postgres-xl,oberstet/postgres-xl,Postgres-XL/Postgres-XL,jmcatamney/gpdb,pavanvd/postgres-xl,techdragon/Postgres-XL,techdragon/Postgres-XL,oberstet/postgres-xl,ashwinstar/gpdb,xinzweb/gpdb,xinzweb/gpdb,yazun/postgres-xl,yazun/postgres-xl,greenplum-db/gpdb,Postgres-XL/Postgres-XL,Postgres-XL/Postgres-XL,50wu/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,zeroae/postgres-xl,oberstet/postgres-xl,greenplum-db/gpdb,adam8157/gpdb,yazun/postgres-xl,oberstet/postgres-xl,ashwinstar/gpdb,xinzweb/gpdb,ovr/postgres-xl,pavanvd/postgres-xl,jmcatamney/gpdb,50wu/gpdb,lisakowen/gpdb,greenplum-db/gpdb,adam8157/gpdb,zeroae/postgres-xl,ashwinstar/gpdb,greenplum-db/gpdb,lisakowen/gpdb,ashwinstar/gpdb,Postgres-XL/Postgres-XL,lisakowen/gpdb,techdragon/Postgres-XL,50wu/gpdb,lisakowen/gpdb,lisakowen/gpdb,lisakowen/gpdb,zeroae/postgres-xl,greenplum-db/gpdb,lisakowen/gpdb,adam8157/gpdb,xinzweb/gpdb,techdragon/Postgres-XL,oberstet/postgres-xl,adam8157/gpdb,greenplum-db/gpdb,yazun/postgres-xl,ashwinstar/gpdb,zeroae/postgres-xl,ovr/postgres-xl,jmcatamney/gpdb,50wu/gpdb,ovr/postgres-xl,jmcatamney/gpdb,ashwinstar/gpdb,adam8157/gpdb,pavanvd/postgres-xl,50wu/gpdb,adam8157/gpdb,greenplum-db/gpdb,zeroae/postgres-xl,50wu/gpdb,jmcatamney/gpdb,xinzweb/gpdb,Postgres-XL/Postgres-XL