fix linking error on Windows.

ProcessLib/HeatTransportBHE/BHE/CreateFlowAndTemperatureControl.cpp

@@ -10,7 +10,7 @@
  */
 
 #include "BaseLib/ConfigTree.h"
-#include "BaseLib/Error.h"
+#include "MathLib/InterpolationAlgorithms/PiecewiseLinearInterpolation.h"
 #include "BaseLib/Algorithm.h"
 
 #include "CreateFlowAndTemperatureControl.h"

ProcessLib/HeatTransportBHE/BHE/CreateFlowAndTemperatureControl.h

@@ -33,7 +33,7 @@ namespace HeatTransportBHE
 {
 namespace BHE
 {
-class RefrigerantProperties;
+struct RefrigerantProperties;
 
 FlowAndTemperatureControl createFlowAndTemperatureControl(
     BaseLib::ConfigTree const& config,