Index: src/runtime/runtime.h
==================================================================
--- src/runtime/runtime.h
+++ src/runtime/runtime.h
@@ -16,11 +16,15 @@
 
 #ifndef __OBJFW_RUNTIME_H__
 #define __OBJFW_RUNTIME_H__
 #include <stdint.h>
 
-#if defined(__has_feature) && __has_feature(objc_arc)
+#ifndef __has_feature
+# define __has_feature(x) 0
+#endif
+
+#if __has_feature(objc_arc)
 # define OBJC_BRIDGE __bridge
 #else
 # define OBJC_BRIDGE
 #endif