@@ -45,10 +45,14 @@
 #endif
 
 #ifndef __has_feature
 # define __has_feature(x) 0
 #endif
+
+#ifndef __has_attribute
+# define __has_attribute(x) 0
+#endif
 
 #ifdef __GNUC__
 # define __GCC_VERSION__ (__GNUC__ * 100 + __GNUC_MINOR__)
 #else
 # define __GCC_VERSION__ 0
@@ -85,10 +89,16 @@
 #if defined(__clang__) || __GCC_VERSION__ >= 406
 # define OF_SENTINEL __attribute__((sentinel))
 #else
 # define OF_SENTINEL
 #endif
+
+#if __has_attribute(objc_requires_super)
+# define OF_REQUIRES_SUPER __attribute__((objc_requires_super))
+#else
+# define OF_REQUIRES_SUPER
+#endif
 
 #ifdef OF_APPLE_RUNTIME
 # if defined(__x86_64__) || defined(__i386__) || defined(__arm__) || \
     defined(__ppc__)
 #  define OF_HAVE_FORWARDING_TARGET_FOR_SELECTOR