Change the IMPORT macros to build an object on-the-fly.

src/AlphaLibMacros.cppo.ml

@@ -191,19 +191,17 @@
 
 (* TEMPORARY use string * loc so as to be able to give a location *)
 
-#define IMPORT_CLASS     __import
 #define IMPORT_FUN(term) CONCAT(import_, term)
 
 #define __IMPORT                                                               \
   exception Unbound = KitImport.Unbound                                        \
-  class ['self] IMPORT_CLASS = object (_ : 'self)                              \
-    inherit [_] map                                                            \
-    inherit [_] KitImport.map                                                  \
-  end                                                                          \
 
 #define IMPORT(term)                                                           \
   let IMPORT_FUN(term) env t =                                                 \
-    new IMPORT_CLASS # VISIT(term) env t                                       \
+    (object                                                                    \
+      inherit [_] map                                                          \
+      inherit [_] KitImport.map                                                \
+    end) # VISIT(term) env t                                                   \
 
 (* -------------------------------------------------------------------------- *)