have the program abort upon encountering NaN

[[Imported from SVN: r1451]]

dune/istl/test/matrixtest.cc

@@ -4,6 +4,9 @@
     \brief Unit tests for the different dynamic matrices provided by ISTL
  */
 #include "config.h"
+
+#include <fenv.h>
+
 #include <dune/common/fmatrix.hh>
 #include <dune/istl/bcrsmatrix.hh>
 #include <dune/istl/matrix.hh>
@@ -276,6 +279,8 @@ void testSolve(const MatrixType& matrix)
 
 int main()
 {
+  feenableexcept(FE_INVALID);
+
   // ////////////////////////////////////////////////////////////
   //   Test the Matrix class -- a scalar dense dynamic matrix
   // ////////////////////////////////////////////////////////////