diff --git a/exfat/libexfat/compiler.h b/exfat/libexfat/compiler.h
index 6edd8ec..3b092a9 100644
--- a/exfat/libexfat/compiler.h
+++ b/exfat/libexfat/compiler.h
@@ -4,7 +4,7 @@
 	showstopper.
 
 	Free exFAT implementation.
-	Copyright (C) 2010-2013  Andrew Nayenko
+	Copyright (C) 2010-2015  Andrew Nayenko
 
 	This program is free software; you can redistribute it and/or modify
 	it under the terms of the GNU General Public License as published by
@@ -24,6 +24,10 @@
 #ifndef COMPILER_H_INCLUDED
 #define COMPILER_H_INCLUDED
 
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ < 199901L)
+#error C99-compliant compiler is required
+#endif
+
 #if defined(__clang__)
 
 #define PRINTF __attribute__((format(printf, 1, 2)))