diff -ur ld64-450.3/src/ld/InputFiles.cpp ld64-450.3+iOS/src/ld/InputFiles.cpp
--- ld64-450.3/src/ld/InputFiles.cpp	2018-09-26 16:04:04.000000000 -1000
+++ ld64-450.3+iOS/src/ld/InputFiles.cpp	2019-12-02 11:22:19.000000000 -1000
@@ -899,6 +899,8 @@
 	opts.setArchitecture(CPU_TYPE_X86_64, CPU_SUBTYPE_X86_64_ALL, ld::kPlatform_macOS, 0);
 #elif __arm__
 	opts.setArchitecture(CPU_TYPE_ARM, CPU_SUBTYPE_ARM_V6, ld::kPlatform_macOS, 0);
+#elif __arm64__
+        opts.setArchitecture(CPU_TYPE_ARM64, CPU_SUBTYPE_ARM_V8, ld::kPlatform_macOS, 0);
 #else
 	#error unknown default architecture
 #endif