From 405bdec807a7b530173ebf018843c4552dfa20c9 Mon Sep 17 00:00:00 2001
From: Rosen Penev <rosenp@gmail.com>
Date: Sat, 6 Jun 2020 11:33:55 -0700
Subject: [PATCH] use std::string_view when available

There's a standard C++ macro to check for its existence.

libstdc++ from GCC makes it available under C++17 and up. libcxx from
LLVM makes it available everywhere.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 ext/lmdb-safe/lmdb-safe.hh | 7 +++----
 pdns/dnsdistdist/views.hh  | 7 +++----
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/ext/lmdb-safe/lmdb-safe.hh b/ext/lmdb-safe/lmdb-safe.hh
index 056a6cd823..16d150fa7d 100644
--- a/ext/lmdb-safe/lmdb-safe.hh
+++ b/ext/lmdb-safe/lmdb-safe.hh
@@ -10,8 +10,9 @@
 #include <string.h>
 #include <mutex>
 
-// apple compiler somehow has string_view even in c++11!
-#if __cplusplus < 201703L && !defined(__APPLE__)
+#ifdef __cpp_lib_string_view
+using std::string_view;
+#else
 #include <boost/version.hpp>
 #if BOOST_VERSION >= 106100
 #include <boost/utility/string_view.hpp>
@@ -20,8 +21,6 @@ using boost::string_view;
 #include <boost/utility/string_ref.hpp>
 using string_view = boost::string_ref;
 #endif
-#else // C++17
-using std::string_view;
 #endif