Fixing the upgrade procedure of WebCalendar 1.2 for PostgreSQL 7.4
When trying to upgrade WebCalendar to 1.2, I fell on a series of errors due to the fact that the upgrade script relies on a dependency to PostgreSQL 8.1, which allows much more ALTER TABLE syntaxes than PostgreSQL 7.4. Nevertheless, there are ways to make it work by updating the upgrade script a little to suit the new syntax.
I'm giving bits of code here, which are directly based on the www/install/sql/update-postgres.sql script, and altered to make it work.
This script can be executed manually as many times as you want with the PostgreSQL user you use for Webcalendar.