From 5c4edf4d7d6dc36917a150298499158a4c20ae99 Mon Sep 17 00:00:00 2001
From: Daniel James <daniel@calamity.org.uk>
Date: Sat, 20 Jan 2018 21:53:36 +0000
Subject: [PATCH] Fix string_view include on gcc 7.2

If it's included in anything earlier than c++-1z it errors.
---
 include/boost/container_hash/hash/hash.hpp | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/include/boost/container_hash/hash/hash.hpp b/include/boost/container_hash/hash/hash.hpp
index 961dda9..f648205 100644
--- a/include/boost/container_hash/hash/hash.hpp
+++ b/include/boost/container_hash/hash/hash.hpp
@@ -69,11 +69,9 @@
 #               define BOOST_HASH_HAS_STRING_VIEW 1
 #               include <string_view>
 #           endif
-#       else
+#       elif defined(__cplusplus) && __cplusplus >= 201703
 #           include <string_view>
-#           if defined(__cpp_lib_string_view) && __cpp_lib_string_view >= 201603
-#               define BOOST_HASH_HAS_STRING_VIEW 1
-#           endif
+#           define BOOST_HASH_HAS_STRING_VIEW 1
 #       endif
 #   endif
 #endif