PostgreSQL

# Changes
* Prevent access to external files/URLs via XML entity references
* Prevent access to external files/URLs via contrib/xml2's xslt_process()
* Prevent too-early recycling of btree index pages
* Fix crash-safety bug with newly-created-or-reset sequences
* Fix race condition in enum-type value comparisons
* Fix txid_current() to report the correct epoch when not in hot standby
* Prevent selection of unsuitable replication connections as the synchronous standby
* Fix bug in startup of Hot Standby when a master transaction has many subtransactions
* Ensure the backup_label file is fsync'd after pg_start_backup()
* Fix timeout handling in walsender processes
* Wake walsenders after each background flush by walwriter
* Fix LISTEN/NOTIFY to cope better with I/O problems, such as out of disk space
* Only allow autovacuum to be auto-canceled by a directly blocked process
* Improve logging of autovacuum cancels
* Fix log collector so that log_truncate_on_rotation works during the very first log rotation after server start
* Fix WITH attached to a nested set operation (UNION/INTERSECT/EXCEPT)
* Ensure that a whole-row reference to a subquery doesn't include any extra GROUP BY or ORDER BY columns
* Fix dependencies generated during ALTER TABLE ... ADD CONSTRAINT USING INDEX
* Fix REASSIGN OWNED to work on extensions
* Disallow copying whole-row references in CHECK constraints and index definitions during CREATE TABLE
* Fix memory leak in ARRAY(SELECT ...) subqueries
* Fix planner to pass correct collation to operator selectivity estimators
* Fix extraction of common prefixes from regular expressions
* Fix bugs with parsing signed hh:mm and hh:mm:ss fields in interval constants
* Fix pg_dump to better handle views containing partial GROUP BY lists
* In PL/Perl, avoid setting UTF8 flag when in SQL_ASCII encoding
* Use Postgres' encoding conversion functions, not Python's, when converting a Python Unicode string to the server encoding in PL/Python
* Fix mapping of PostgreSQL encodings to Python encodings in PL/Python
* Report errors properly in contrib/xml2's xslt_process()
* Update time zone data files to tzdata release 2012e for DST law changes in Morocco and Tokelau