Allow ALTER TABLE name {OF type | NOT OF}.

This syntax allows a standalone table to be made into a typed table,
or a typed table to be made standalone.  This is possibly a mildly
useful feature in its own right, but the real motivation for this
change is that we need it to make pg_upgrade work with typed tables.
This doesn't actually fix that problem, but it's necessary
infrastructure.

Noah Misch

src/include/commands/tablecmds.h

@@ -56,6 +56,8 @@ extern void find_composite_type_dependencies(Oid typeOid,
 								 Relation origRelation,
 								 const char *origTypeName);
 
+extern void check_of_type(HeapTuple typetuple);
+
 extern AttrNumber *varattnos_map(TupleDesc olddesc, TupleDesc newdesc);
 extern AttrNumber *varattnos_map_schema(TupleDesc old, List *schema);
 extern void change_varattnos_of_a_node(Node *node, const AttrNumber *newattno);