--- src/osd/modules/file/posixfile.cpp	2020-12-08 16:14:00.000000000 -0500
+++ src/osd/modules/file/posixfile.cpp	2020-12-08 16:15:00.000000000 -0500
@@ -37,6 +37,11 @@
 #endif
 #endif
 
+// Fix for MacOS compilation errors
+#if defined(__APPLE__) && !defined(_DARWIN_C_SOURCE)
+#define _DARWIN_C_SOURCE
+#endif
+
 // MAME headers
 #include "posixfile.h"
 #include "unicode.h"