User locations fail with query error on PostgreSQL

This query is non-standards compliant and it fails on PostgreSQL, although it works on MySQL:
SELECT u.name, MAX(r.rid) as role, i.uid, i.lid, l.latitude, l.longitude FROM users u INNER JOIN location_instance i ON u.uid = i.uid INNER JOIN location l ON i.lid = l.lid LEFT JOIN users_roles r ON i.uid = r.uid WHERE u.status = 1 AND u.access != 0 AND (l.latitude != 0 OR l.longitude != 0) GROUP BY i.uid, i.lid
in gmap_location.module on line 133

The proper query should be:
SELECT u.name, MAX(r.rid) as role, i.uid, i.lid, l.latitude, l.longitude FROM users u INNER JOIN location_instance i ON u.uid = i.uid INNER JOIN location l ON i.lid = l.lid LEFT JOIN users_roles r ON i.uid = r.uid WHERE u.status = 1 AND u.access != 0 AND (l.latitude != 0 OR l.longitude != 0) GROUP BY i.uid, i.lid, u.name, l.latitude, l.longitude