Missing Linux C++ #include.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@206 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/simulator/simpath.cc

@@ -28,6 +28,7 @@
 #include "simutil.h"
 #include <stdio.h>
 #include <iostream>
+#include <math.h>
 
 using std::cout;
 using std::endl;