Remove warnings appearing only in Clang

dune/dorie/solver/operator_DG.hh

@@ -628,7 +628,7 @@ public:
             else
               relCond = relCond_n;
           }
-          else if (upwinding == RichardsDGUpwinding::none)
+          else // (upwinding == RichardsDGUpwinding::none)
           {
             // harmonic average of conductivity factors
             relCond = 2 * relCond_s * relCond_n / (relCond_s + relCond_n);
@@ -719,7 +719,7 @@ public:
             else
               relCond = relCond_n;
           }
-          else if (upwinding == RichardsDGUpwinding::none)
+          else // (upwinding == RichardsDGUpwinding::none)
           {
             // harmonic average of conductivity factors
             relCond = 2 * relCond_s * relCond_n / (relCond_s + relCond_n);

dune/dorie/solver/param_base.hh

@@ -117,6 +117,8 @@ namespace Dune {
         }
       }
 
+      virtual ~ParameterizationBase () = default;
+
       /// Iterate through parameter array and read each one from the H5 file
       void read_parameters()
       {

dune/dorie/solver/util_boundary_condition.hh

@@ -312,7 +312,7 @@ namespace Dorie{
 				unsigned int xGlobalIndex;
 				if (bcSide == BC::North || bcSide == BC::South)
 					xGlobalIndex = 0;
-				else if (bcSide == BC::West || bcSide == BC::East)
+				else // (bcSide == BC::West || bcSide == BC::East)
 					xGlobalIndex = 1;
 
 				// run along axis

dune/dorie/solver/util_interpolator.hh

@@ -37,6 +37,8 @@ namespace Dune {
       config(config_), helper(helper_), verbose(verbose_), eps(1e-9), initialized(false), method(method_)
       {}
 
+      virtual ~InterpolatorBase () = default;
+
        RF evaluate(const Array& field, const Domain& pos)
       {
         for(Index i = 0; i < dim; i++)