in CREATE TABLE, but give a warning notice. Clean up inconsistent
handling of defaults and NOT NULL flags from multiply-inherited columns.
Per pghackers discussion 28-Mar through 30-Mar.
and revert documentation to describe the existing INHERITS clause
instead, per recent discussion in pghackers. Also fix implementation
of SQL_inheritance SET variable: it is not cool to look at this var
during the initial parsing phase, only during parse_analyze(). See
recent bug report concerning misinterpretation of date constants just
after a SET TIMEZONE command. gram.y really has to be an invariant
transformation of the query string to a raw parsetree; anything that
can vary with time must be done during parse analysis.