+#include <stdarg.h>
+
+#include "portability.h"
+
+/*
+ * If we're compiling with Visual Studio, make sure we have at least
+ * VS 2015 or later, so we have sufficient C99 support.
+ *
+ * XXX - verify that we have at least C99 support on UN*Xes?
+ *
+ * What about MinGW or various DOS toolchains? We're currently assuming
+ * sufficient C99 support there.
+ */
+#if defined(_MSC_VER)
+ /*
+ * Compiler is MSVC. Make sure we have VS 2015 or later.
+ */
+ #if _MSC_VER < 1900
+ #error "Building libpcap requires VS 2015 or later"
+ #endif
+#endif
+