ndnboost: Also rename BOOST_ to NDNBOOST_
diff --git a/include/ndnboost/preprocessor/facilities/empty.hpp b/include/ndnboost/preprocessor/facilities/empty.hpp
index 46db190..e3fd3ea 100644
--- a/include/ndnboost/preprocessor/facilities/empty.hpp
+++ b/include/ndnboost/preprocessor/facilities/empty.hpp
@@ -11,11 +11,11 @@
 #
 # /* See http://www.boost.org for most recent version. */
 #
-# ifndef BOOST_PREPROCESSOR_FACILITIES_EMPTY_HPP
-# define BOOST_PREPROCESSOR_FACILITIES_EMPTY_HPP
+# ifndef NDNBOOST_PREPROCESSOR_FACILITIES_EMPTY_HPP
+# define NDNBOOST_PREPROCESSOR_FACILITIES_EMPTY_HPP
 #
-# /* BOOST_PP_EMPTY */
+# /* NDNBOOST_PP_EMPTY */
 #
-# define BOOST_PP_EMPTY()
+# define NDNBOOST_PP_EMPTY()
 #
 # endif