Index: src/OFObject.m
==================================================================
--- src/OFObject.m
+++ src/OFObject.m
@@ -21,10 +21,14 @@
 #include <string.h>
 
 #include <assert.h>
 
 #include <sys/time.h>
+
+#ifdef OF_APPLE_RUNTIME
+# include <dlfcn.h>
+#endif
 
 #import "OFObject.h"
 #import "OFArray.h"
 #import "OFLocalization.h"
 #import "OFTimer.h"
@@ -57,14 +61,10 @@
 # import "atomic.h"
 #elif defined(OF_HAVE_THREADS)
 # import "threading.h"
 #endif
 
-#ifdef OF_APPLE_RUNTIME
-extern double NSFoundationVersionNumber;
-#endif
-
 #if defined(OF_HAVE_FORWARDING_TARGET_FOR_SELECTOR)
 extern id of_forward(id, SEL, ...);
 extern struct stret of_forward_stret(id, SEL, ...);
 #else
 # define of_forward of_method_not_found
@@ -226,11 +226,11 @@
 	 * Foundation.
 	 *
 	 * Unfortunately, there is no way to check if a forward handler has
 	 * already been set, so this is the best we can do.
 	 */
-	if (&NSFoundationVersionNumber == NULL)
+	if (dlsym(RTLD_DEFAULT, "NSFoundationVersionNumber") == NULL)
 		objc_setForwardHandler((void *)&of_forward,
 		    (void *)&of_forward_stret);
 #else
 	objc_setForwardHandler((IMP)&of_forward, (IMP)&of_forward_stret);
 #endif