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/encoding/block.hpp b/src/encoding/block.hpp
index 031b00f..177d1f2 100644
--- a/src/encoding/block.hpp
+++ b/src/encoding/block.hpp
@@ -24,11 +24,9 @@
 #ifndef NDN_ENCODING_BLOCK_HPP
 #define NDN_ENCODING_BLOCK_HPP
 
-#include "../common.hpp"
-
 #include "buffer.hpp"
-#include "tlv.hpp"
 #include "encoding-buffer-fwd.hpp"
+#include "tlv.hpp"
 
 namespace boost {
 namespace asio {