[math] trying to fix blockvector fail for good

dune/stuff/common/math.hh

@@ -33,8 +33,13 @@ namespace boost {
 namespace math {
 //! isinf specialization for Dune::StraightenBlockVector
 template <class BlockVectorImp, class DofImp>
+#if DUNE_VERSION_NEWER(DUNE_FEM, 1, 4)
 inline bool isinf(const Dune::Fem::StraightenBlockVector<BlockVectorImp, DofImp>& x)
 {
+#else
+inline bool isinf(const Dune::StraightenBlockVector<BlockVectorImp, DofImp>& x)
+{
+#endif
   for (size_t i = 0; i < x.size(); ++i) {
     if (std::isinf(x[i]))
       return true;