--- a/include/libnet.h
+++ b/include/libnet.h
@@ -32,6 +32,17 @@
 #ifndef __LIBNET_H
 #define __LIBNET_H
 
+#include <endian.h>
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+# define LIBNET_LIL_ENDIAN 1
+#else
+# if __BYTE_ORDER == __BIG_ENDIAN
+#  define LIBNET_BIG_ENDIAN 1
+# else
+#  error unrecognized __BYTE_ORDER
+# endif
+#endif
+
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>