diff --git a/common/emitter/legacy_instructions.h b/common/emitter/legacy_instructions.h
index fdd9304cf1..5b731fd48b 100644
--- a/common/emitter/legacy_instructions.h
+++ b/common/emitter/legacy_instructions.h
@@ -22,6 +22,10 @@
 #define ATTR_DEP
 #endif
 
+#ifdef FSCALE
+# undef FSCALE // Defined in a macOS header
+#endif
+
 //------------------------------------------------------------------
 // legacy jump/align functions
 //------------------------------------------------------------------