gnucash: /usr/lib/libgnc-backend-postgres.so: cannot open shared object file: No such file or directory

failed to load gnc-backend-postgres from /usr/lib

loading system configuration
looking for /etc/gnucash/config
trying to load /etc/gnucash/config
loading user configuration
looking for /home/dave/.gnucash/config-2.0.user
looking for /home/dave/.gnucash/config-1.8.user
looking for /home/dave/.gnucash/config-1.6.user
looking for /home/dave/.gnucash/config.user
loading auto configuration
looking for /home/dave/.gnucash/config-2.0.auto
looking for /home/dave/.gnucash/config-1.8.auto
looking for /home/dave/.gnucash/config-1.6.auto
looking for /home/dave/.gnucash/config.auto
loading saved reports
looking for /home/dave/.gnucash/saved-reports-2.0
looking for /home/dave/.gnucash/saved-reports-1.8
loading stylesheets
looking for /home/dave/.gnucash/stylesheets-2.0
trying to load /home/dave/.gnucash/stylesheets-2.0