Help with gram.y (UNDER)

Can someone give be a bit of help with gram.y to get this UNDER syntax
right? I did what I though was the obvious  syntax, but it no longer
accepts a plain create table after this change...

OptUnder: UNDER relation_name_list     { $$ = $2; }       | /*EMPTY*/       { $$ = NIL; } ;



CreateStmt:  CREATE OptTemp TABLE relation_name OptUnder '('
OptTableElementList ')' OptInherit        {                   /*etc */        }    ;

The full patch is here...
ftp://ftp.tech.com.au/pub/diff.x