diff --git a/src/arg_int.c b/src/arg_int.c
index bc10012..ffcd408 100644
--- a/src/arg_int.c
+++ b/src/arg_int.c
@@ -33,6 +33,9 @@ USA.
 #include <ctype.h>
 
 /* local error codes */
+#ifdef EOVERFLOW
+#undef EOVERFLOW
+#endif
 enum {EMINCOUNT=1,EMAXCOUNT,EBADINT,EOVERFLOW};
 
 static void resetfn(struct arg_int *parent)