diff -ru a/RtMidi.cpp b/RtMidi.cpp
--- a/RtMidi.cpp	2021-12-23 16:46:33.000000000 -0500
+++ b/RtMidi.cpp	2021-12-23 16:48:19.000000000 -0500
@@ -39,6 +39,9 @@
 
 #include "RtMidi.h"
 #include <sstream>
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
 
 #if defined(__MACOSX_CORE__)
   #if TARGET_OS_IPHONE