diff --git a/build/osx/arm64_osx.mk b/build/osx/arm64_osx.mk
new file mode 100644
index 0000000..bfe437b
--- /dev/null
+++ b/build/osx/arm64_osx.mk
@@ -0,0 +1,14 @@
+##
+## arm64 OSX (Apple Silicon) Makefile
+## Tested on Apple M4
+## Use make
+##
+TargetCPU  :=arm64
+OS         :=osx
+# -include: modern macOS g++ is clang++/libc++, which lacks abi::__forced_unwind
+# that the OSX sources expect from libstdc++-era toolchains.
+CXXFLAGS   := -O3 -fPIC -pedantic -arch arm64 -include forced_unwind_stub.h
+
+# Standard part
+
+include common.mk
diff --git a/build/osx/forced_unwind_stub.h b/build/osx/forced_unwind_stub.h
new file mode 100644
index 0000000..3cdaed1
--- /dev/null
+++ b/build/osx/forced_unwind_stub.h
@@ -0,0 +1,6 @@
+// Apple libc++ has no abi::__forced_unwind (Linux libstdc++ pthread cancel).
+// Force-included by arm64_osx.mk so upstream snap_threads.cpp compiles unchanged.
+#pragma once
+namespace __cxxabiv1 {
+struct __forced_unwind {};
+}