diff --git a/libfreefare/freefare_internal.h b/libfreefare/freefare_internal.h
index 9474adf..0425bb5 100644
--- a/libfreefare/freefare_internal.h
+++ b/libfreefare/freefare_internal.h
@@ -356,7 +356,7 @@ struct mifare_ultralight_tag {
  * BUFFER_APPEND_LE (buffer, data, 3, 4);
  */
 
-#if _BYTE_ORDER != _LITTLE_ENDIAN
+#if defined(_BYTE_ORDER) && (_BYTE_ORDER != _LITTLE_ENDIAN)
 #define BUFFER_APPEND_LE(buffer, data, data_size, field_size) \
     do { \
 	size_t __data_size = data_size; \