Correction of the compilation issue in optimized mode (./waf -d optimized)
diff --git a/model/ccnx-interest-header.cc b/model/ccnx-interest-header.cc
index d44ac45..c77c441 100644
--- a/model/ccnx-interest-header.cc
+++ b/model/ccnx-interest-header.cc
@@ -211,7 +211,7 @@
 void
 CcnxInterestHeader::Serialize (Buffer::Iterator start) const
 {
-  size_t size = CcnxEncodingHelper::Serialize (start, *this);
+  size_t size __attribute__ ((__unused__)) = CcnxEncodingHelper::Serialize (start, *this);
   
   NS_LOG_INFO ("Serialize size = " << size);
 }