Fix it for lex.

 datetime and timespan.

spi.c: functions to prepare/run and preserve plans for
       duration of transaction/session. Some data utilities.

and O'Reilly "lex & yacc" book claims ATT-lex has trouble with comments.

RelationBuildTriggers() & FreeTriggerDesc() in trigger.c

Fix up results labels on queries.
Update existing queries which now return good results.