Hack of a fix for TasmanianSparseGrid dependency on M_PI.

radixsparsegrids/sparse_grids.hh

@@ -3,6 +3,9 @@
 
 #include <string>
 #include <vector>
+#ifndef M_PI
+#define _USE_MATH_DEFINES
+#endif
 #include "TasmanianSparseGrid.hpp"
 
 namespace radix {
@@ -43,7 +46,7 @@ class SparseGrids
   TasGrid::TasmanianSparseGrid mGrid;
   double* mPoints;
   std::vector<double> mOutputValues;
-  
+
 };
 
 } // namespace radix