Add virtual destructor to MatchData

libwccl/values/matchdata.h

@@ -11,7 +11,7 @@ namespace Wccl {
  * - VectorMatch, TokenMatch or AnnotationMatch.
  * (empty VectorMatch should be default option)
  */
-class MatchData// : boost::noncopyable
+class MatchData
 {
 public:
 
@@ -38,6 +38,8 @@ public:
 
 	virtual std::string to_raw_string() const = 0;
 
+	virtual ~MatchData() {}
+
 protected:
 	virtual MatchData* clone_internal() const = 0;
 };