+extern void nitni_global_ref_incr(void*);
+extern void nitni_global_ref_decr(void*);
+#ifndef Sys_incr_ref
+ #define Sys_incr_ref(from) nitni_global_ref_incr((Sys)(from))
+#endif
+#ifndef Sys_decr_ref
+ #define Sys_decr_ref(from) nitni_global_ref_decr((Sys)(from))
+#endif