Pass headercheck

src/enums.hh

+#ifndef ENUMS_HH
+#define ENUMS_HH
+
 struct Config {
   enum model {
     Laursen,
@@ -8,3 +11,4 @@ struct Config {
     Ruina
   };
 };
+#endif

src/test-gradient-method-helper.hh

+#ifndef TEST_GRADIENT_METHOD_HELPER_HH
+#define TEST_GRADIENT_METHOD_HELPER_HH
+
 #include <boost/format.hpp>
 
 #include <dune/tnnmg/problem-classes/bisection.hh>
@@ -21,3 +24,4 @@ double functionTester(Dune::SampleFunctional<dim> J,
   std::cout << boost::format("%8g -> %e") % original % final << std::endl;
   return final;
 }
+#endif

src/test-gradient-method-nicefunction.hh

+#ifndef TEST_GRADIENT_METHOD_NICEFUNCTION_HH
+#define TEST_GRADIENT_METHOD_NICEFUNCTION_HH
+
+#include <cassert>
+
 #include <dune/tectonic/nicefunction.hh>
 
 namespace Dune {
@@ -113,3 +118,4 @@ class HorribleFunctionLogarithmic : public MyFunction {
   }
 };
 }
+#endif