Add location field to DefElem

Add a location field to the DefElem struct, used to parse many utility
commands.  Update various error messages to supply error position
information.

To propogate the error position information in a more systematic way,
create a ParseState in standard_ProcessUtility() and pass that to
interested functions implementing the utility commands.  This seems
better than passing the query string and then reassembling a parse state
ad hoc, which violates the encapsulation of the ParseState type.

Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>

src/backend/parser/parse_utilcmd.c

@@ -294,7 +294,8 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 		 * overridden if an inherited table has oids.
 		 */
 		stmt->options = lcons(makeDefElem("oids",
-						  (Node *) makeInteger(cxt.hasoids)), stmt->options);
+										  (Node *) makeInteger(cxt.hasoids), -1),
+							  stmt->options);
 	}
 
 	foreach(elements, stmt->tableElts)
@@ -482,7 +483,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 								 makeString(cxt->relation->relname),
 								 makeString(column->colname));
 		altseqstmt->options = list_make1(makeDefElem("owned_by",
-													 (Node *) attnamelist));
+													 (Node *) attnamelist, -1));
 
 		cxt->alist = lappend(cxt->alist, altseqstmt);