diff --git a/lib/setup.h b/lib/setup.h
index d68782366576b6a50156db633a55a3ac2723deb3..c3a308abd1edb3f717f62e9e356e226697f8a814 100644
--- a/lib/setup.h
+++ b/lib/setup.h
@@ -272,6 +272,9 @@
 #ifdef word
 #undef word
 #endif
+#ifdef byte
+#undef byte
+#endif
 
 #else /* MSDOS */