meta-info: Reducing use of inline methods

Change-Id: I6630d6bdd8d7277b86e7d8adaaff67762975cf13
diff --git a/src/data.cpp b/src/data.cpp
index 77fc3c9..0a2e3fb 100644
--- a/src/data.cpp
+++ b/src/data.cpp
@@ -20,6 +20,7 @@
  */
 
 #include "data.hpp"
+#include "encoding/block-helpers.hpp"
 #include "util/crypto.hpp"
 
 namespace ndn {