psql backward compatibility fix

For servers older than 8.3, sort display of child tables by relname instead
of oid::regclass::text, because the cast from regclass to text did not work
back then.  The older display may be slightly worse when different schemas
are involved, but that should be rare enough.

src/bin/psql/describe.c

@@ -8,7 +8,7 @@
  *
  * Copyright (c) 2000-2009, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/bin/psql/describe.c,v 1.222 2009/07/07 19:05:57 petere Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/describe.c,v 1.223 2009/07/07 20:32:20 petere Exp $
  */
 #include "postgres_fe.h"
 
@@ -1821,7 +1821,10 @@ describeOneTableDetails(const char *schemaname,
 		PQclear(result);
 
 		/* print child tables */
-		printfPQExpBuffer(&buf, "SELECT c.oid::pg_catalog.regclass FROM pg_catalog.pg_class c, pg_catalog.pg_inherits i WHERE c.oid=i.inhrelid AND i.inhparent = '%s' ORDER BY c.oid::pg_catalog.regclass::text;", oid);
+		if (pset.sversion >= 80300)
+			printfPQExpBuffer(&buf, "SELECT c.oid::pg_catalog.regclass FROM pg_catalog.pg_class c, pg_catalog.pg_inherits i WHERE c.oid=i.inhrelid AND i.inhparent = '%s' ORDER BY c.oid::pg_catalog.regclass::text;", oid);
+		else
+			printfPQExpBuffer(&buf, "SELECT c.oid::pg_catalog.regclass FROM pg_catalog.pg_class c, pg_catalog.pg_inherits i WHERE c.oid=i.inhrelid AND i.inhparent = '%s' ORDER BY c.relname;", oid);
 
 		result = PSQLexec(buf.data, false);
 		if (!result)