MSVC 2013 defines conformant round(), workaround not needed

platforms/reference/src/ReferenceTabulatedFunction.cpp

@@ -33,13 +33,20 @@
 #include "openmm/OpenMMException.h"
 #include "openmm/internal/SplineFitter.h"
 
-#ifdef _MSC_VER
+#if _MSC_VER
+
+#if _MSC_VER < 1800
 /**
  * We need to define this ourselves, since Visual Studio is missing round() from cmath.
  */
 static int round(double x) {
     return (int) (x+0.5);
 }
+#else
+#include <cmath>
+#endif  // MSC_VER < 1800
+
+
 #else
 #include <cmath>
 #endif