Repair possible failure to update hint bits on disk
Under rare circumstances this oversight could lead to "could not access transaction status" failures, which qualifies it as a potential-data-loss bug.
Ensure that hashed outer join does not miss tuples
Very large left joins using a hash join plan could fail to output unmatched left-side rows given just the right data distribution.
Disallow running pg_ctl as root
This is to guard against any possible security issues.
Avoid using temp files in /tmp in make_oidjoins_check
This has been reported as a security issue, though it's hardly worthy of concern since there is no reason for non-developers to use this script anyway.