--- Source/WTF/wtf/Platform.h.orig
+++ Source/WTF/wtf/Platform.h
@@ -186,6 +186,11 @@
 
 #endif
 
+/* CPU(ARM64) - Apple */
+#if (defined(__arm64__) && defined(__APPLE__)) || defined(__aarch64__)
+#define WTF_CPU_ARM64 1
+#endif
+
 /* CPU(ARM) - ARM, any version*/
 #define WTF_ARM_ARCH_AT_LEAST(N) (CPU(ARM) && WTF_ARM_ARCH_VERSION >= N)