This update contains a critical fix to the pg_upgrade utility
which prevents significant downtime issues. Do not use
pg_upgrade without installing this update first.
The issue with pg_upgrade and the fix are detailed on the PostgreSQL
wiki: http://wiki.postgresql.org/wiki/20110408pg_upgrade_fix
Users who have already used pg_upgrade should run the database repair
script given on that page on their databases as soon as possible.
See the release notes for each version at
http://www.postgresql.org/docs/current/static/release.html for a full
list of changes with details.
Allow the username of the postgresql user to configurable for 8.4 and 9.0.
Largely inspired by the work of Jason Helfman [153668, 153136].
Change PGUSER knob to PG_USER not to clash with PGUSER environment.
PR: 153668, 153136, 155493, 155137
