The RCLASS_SUPER define is present in both Ruby 1.8 and 1.9.

Direct access to "super" no longer works in 1.9 (the field is
not there), but the define continues to work properly.

	-mi

--- src/bdb1.c	2006-09-20 12:41:01.000000000 -0400
+++ src/bdb1.c	2011-09-02 12:27:34.000000000 -0400
@@ -692,5 +692,5 @@
 	    break;
 	}
-	cl = RCLASS(cl)->super;
+	cl = RCLASS_SUPER(cl);
     }
     if (!cl) {