Log Message:
Changes 8.3.7:
* Prevent error recursion crashes when encoding conversion fails.
* Disallow "CREATE CONVERSION" with the wrong encodings for the
  specified conversion function.
* Fix xpath() to not modify the path expression unless necessary, and
  to make a saner attempt at it when necessary.
* Fix core dump when to_char() is given format codes that are
  inappropriate for the type of the data argument.
* Fix possible failure in text search when C locale is used with a
  multi-byte encoding.
* Fix extreme inefficiency in text search parser's handling of an
  email-like string containing multiple @ characters.
* Fix planner problem with sub-"SELECT" in the output list of a
  larger subquery.
* Fix decompilation of CASE WHEN with an implicit coercion.
* Fix possible misassignment of the owner of a TOAST table's rowtype.
* Change "UNLISTEN" to exit quickly if the current session has never
  executed any "LISTEN" command.
* Fix PL/pgSQL to not treat INTO after "INSERT" as an INTO-variables
  clause anywhere in the string, not only at the start; in
  particular, don't fail for "INSERT INTO" within "CREATE RULE".
* Clean up PL/pgSQL error status variables fully at block exit.
* Retry failed calls to CallNamedPipe() on Windows.
* Add MUST (Mauritius Island Summer Time) to the default list of
  known timezone abbreviations.