added libguardians.ss

src/libguardians.ss

@@ -0,0 +1,20 @@
+
+(let ()
+  (define make-guardian
+    (lambda ()
+      (let ([tc
+             (let ([x (cons #f #f)])
+               (cons x x))])
+        (case-lambda
+          [()
+           (and (not (eq? (car tc) (cdr tc)))
+                (let ([x (car tc)])
+                  (let ([y (car x)])
+                    (set-car! tc (cdr x))
+                    (set-car! x #f)
+                    (set-cdr! x #f)
+                    y)))]
+          [(obj) 
+           (foreign-call "ikrt_register_guardian" tc obj)
+           (void)]))))
+  (primitive-set! 'make-guardian make-guardian))