diff --git a/Makefile.common b/Makefile.common
index fe1782b..94e343a 100644
--- a/Makefile.common
+++ b/Makefile.common
@@ -17,9 +17,18 @@ ifeq "$(NATIVE_COMPILER)" ""
 # $(NATIVE_COMPILER) was added in 4.09: use $(ARCH) for 4.06-4.08
 ifeq "$(ARCH)" "none"
 NATIVE_COMPILER = false
+NATDYNLINK = false
 else
 NATIVE_COMPILER = true
 endif
+else
+# OCaml 4.x only sets NATIVE_COMPILER = false when --disable-native-compiler is
+# given explicitly. Legacy architectures not supported by the native compiler
+# then end up with NATIVE_COMPILER=true and ARCH=none
+ifeq "$(ARCH)" "none"
+NATIVE_COMPILER = false
+NATDYNLINK = false
+endif
 endif
 
 # PROFILE=dev or PROFILE=release