Add -Wextra-semi -Wundefined-func-template to the default CXXFLAGS

And fix the resulting compilation errors.

Change-Id: I16f679836a0cf2a3ff5dfcf6f6b67bfbfe4cdbd7
Refs: #4248
diff --git a/src/util/regex/regex-pattern-list-matcher.hpp b/src/util/regex/regex-pattern-list-matcher.hpp
index fb0743b..ccac4b8 100644
--- a/src/util/regex/regex-pattern-list-matcher.hpp
+++ b/src/util/regex/regex-pattern-list-matcher.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2013-2015 Regents of the University of California.
+/*
+ * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -37,14 +37,9 @@
 public:
   RegexPatternListMatcher(const std::string& expr, shared_ptr<RegexBackrefManager> backrefManager);
 
-  virtual
-  ~RegexPatternListMatcher()
-  {
-  };
-
 protected:
-  virtual void
-  compile();
+  void
+  compile() override;
 
 private:
   bool
@@ -55,9 +50,6 @@
 
   int
   extractRepetition(size_t index);
-
-private:
-
 };
 
 } // namespace ndn
@@ -193,7 +185,6 @@
   }
 }
 
-
 } // namespace ndn
 
 #endif // NDN_UTIL_REGEX_REGEX_PATTERN_LIST_MATCHER_HPP