diff --git a/src/stdafx.h b/src/stdafx.h
--- a/src/stdafx.h
+++ b/src/stdafx.h
@@ -156,6 +156,17 @@
 	#else
 		#define FINAL
 	#endif
+
+	/* Use fallthrough attribute where supported */
+	#if __GNUC__ >= 7
+		#if __cplusplus > 201402L // C++17
+			#define FALLTHROUGH [[fallthrough]]
+		#else
+			#define FALLTHROUGH __attribute__((fallthrough))
+		#endif
+	#else
+		#define FALLTHROUGH
+	#endif
 #endif /* __GNUC__ */
 
 #if defined(__WATCOMC__)
@@ -164,6 +175,7 @@
 	#define GCC_PACK
 	#define WARN_FORMAT(string, args)
 	#define FINAL
+	#define FALLTHROUGH
 	#include <malloc.h>
 #endif /* __WATCOMC__ */
 
@@ -235,6 +247,13 @@
 	#define WARN_FORMAT(string, args)
 	#define FINAL sealed
 
+	/* fallthrough attribute, VS 2017 */
+	#if (_MSC_VER >= 1910)
+		#define FALLTHROUGH [[fallthrough]]
+	#else
+		#define FALLTHROUGH
+	#endif
+
 	#if defined(WINCE)
 		int CDECL vsnprintf(char *str, size_t size, const char *format, va_list ap);
 	#endif