Add getter for data member

Author: reuk

src/goto-diff/unified_diff.cpp

@@ -396,3 +396,8 @@ void unified_difft::output(std::ostream &os) const
       os);
   }
 }
+
+const unified_difft::differences_mapt &unified_difft::differences_map() const
+{
+  return differences_map_;
+}

src/goto-diff/unified_diff.h

@@ -103,6 +103,8 @@ class unified_difft
          false));
   }
 
+  const differences_mapt &differences_map() const;
+
 private:
   differences_mapt differences_map_;
 };