diff --git a/contrib/MathEval/xmath.cpp b/contrib/MathEval/xmath.cpp
index 48c70da1bf1e469495fc9c5974495ec368d4520f..2fd8c6f85ce3901944ecd1c735ed8f6e836d9a17 100644
--- a/contrib/MathEval/xmath.cpp
+++ b/contrib/MathEval/xmath.cpp
@@ -127,7 +127,7 @@ x_heavs(double x) //, double eps)
 #endif
 
 #if !defined(NAN)
-#define NAN (1./0.)
+#define NAN 1.100
 #endif
 
 double