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/meta-info.cpp b/src/meta-info.cpp
index dcafb18..e19c11d 100644
--- a/src/meta-info.cpp
+++ b/src/meta-info.cpp
@@ -152,8 +152,7 @@
 
   // FreshnessPeriod
   if (m_freshnessPeriod != DEFAULT_FRESHNESS_PERIOD) {
-    totalLength += prependNonNegativeIntegerBlock(encoder, tlv::FreshnessPeriod,
-                                                  m_freshnessPeriod.count());
+    totalLength += prependNonNegativeIntegerBlock(encoder, tlv::FreshnessPeriod, m_freshnessPeriod.count());
   }
 
   // ContentType
@@ -166,11 +165,7 @@
   return totalLength;
 }
 
-template size_t
-MetaInfo::wireEncode<encoding::EncoderTag>(EncodingImpl<encoding::EncoderTag>& encoder) const;
-
-template size_t
-MetaInfo::wireEncode<encoding::EstimatorTag>(EncodingImpl<encoding::EstimatorTag>& encoder) const;
+NDN_CXX_DEFINE_WIRE_ENCODE_INSTANTIATIONS(MetaInfo);
 
 const Block&
 MetaInfo::wireEncode() const