fix compilation in windows

constraint_solver/constraint_solver.h

@@ -3704,11 +3704,15 @@ class Assignment : public PropagationBaseObject {
   // Loads an assignment from a file; does not add variables to the
   // assignment (only the variables contained in the assignment are modified).
   bool Load(const string& filename);
+#if !defined(SWIG)
   bool Load(File* file);
+#endif
   void Load(const AssignmentProto& proto);
   // Saves the assignment to a file.
   bool Save(const string& filename);
+#if !defined(SWIG)
   bool Save(File* file);
+#endif
   void Save(AssignmentProto* const proto);
 
   void AddObjective(IntVar* const v);