net+util: fix build with gcc-7
Introduce an NDN_CXX_FALLTHROUGH macro to simplify
annotating switch cases that fall through.
Update code-style to recommend using NDN_CXX_FALLTHROUGH.
Change-Id: I80e4ff8d16a09f6ec9343f0480bc57ae0fcd1be4
diff --git a/src/util/backports-ostream-joiner.hpp b/src/util/backports-ostream-joiner.hpp
index 24a161c..75d53dd 100644
--- a/src/util/backports-ostream-joiner.hpp
+++ b/src/util/backports-ostream-joiner.hpp
@@ -27,16 +27,12 @@
#ifndef NDN_UTIL_BACKPORTS_OSTREAM_JOINER_HPP
#define NDN_UTIL_BACKPORTS_OSTREAM_JOINER_HPP
-#include "../common.hpp"
+#include "backports.hpp"
-#if __cplusplus >= 201402L
-# ifdef __has_include
-# if __has_include(<experimental/iterator>)
-# include <experimental/iterator>
-# if __cpp_lib_experimental_ostream_joiner >= 201411
-# define NDN_CXX_HAVE_EXPERIMENTAL_OSTREAM_JOINER
-# endif
-# endif
+#if (__cplusplus >= 201402L) && NDN_CXX_HAS_INCLUDE(<experimental/iterator>)
+# include <experimental/iterator>
+# if __cpp_lib_experimental_ostream_joiner >= 201411
+# define NDN_CXX_HAVE_EXPERIMENTAL_OSTREAM_JOINER
# endif
#endif