If postgres should normally be the owner of /usr/local/pqsql/lib directory ... then postgres should have been able to create that symlink.
Please don't do that. Postgres should NOT be the owner of the binaries or the source. The only thing the postgres user may own is it's .../data directory and the datafiles therein. If you carefully examine your installation, you will find that it is quite rare for a service (running with a UID other than root) to also own the binaries. The reason is simple: If a service has been cracked, it will not be able to change it's own binaries to install trojans.
