Make sure we respect our "canonical SQL version" flag when automagically building our mapping list of internal PG data types to SQL types. This was causing a bug in which a SQL_CHAR type was getting mapped to a pg "char" (single character) rather than the expected bpchar (both map back to SQL_CHAR). This was causing bind_param to fail, if it was using the returned types. Per email to dbi-dev list from H.Merijn Brand 2013/03/04.