diff --git a/model/src/constants.F90 b/model/src/constants.F90
index 1f79e30072..3615f4b6cc 100644
--- a/model/src/constants.F90
+++ b/model/src/constants.F90
@@ -1,4 +1,9 @@
 #include "w3macros.h"
+!
+#ifndef ENDIANNESS
+#define ENDIANNESS "native"
+#endif
+!
 !/ ------------------------------------------------------------------- /
       MODULE CONSTANTS
 !/