From f99dee19178eda18e15b9923e8bad366095d4f63 Mon Sep 17 00:00:00 2001
From: Daniel James <daniel@calamity.org.uk>
Date: Tue, 19 Dec 2017 12:11:36 +0000
Subject: [PATCH] Use predef for detecting piecewise construction

And detect it for recent dinkumware.
---
 include/boost/unordered/detail/fwd.hpp            | 13 +++++++++----
 include/boost/unordered/detail/implementation.hpp |  1 -
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/include/boost/unordered/detail/fwd.hpp b/include/boost/unordered/detail/fwd.hpp
index 75030a9a..e749ce67 100644
--- a/include/boost/unordered/detail/fwd.hpp
+++ b/include/boost/unordered/detail/fwd.hpp
@@ -11,6 +11,8 @@
 #pragma once
 #endif
 
+#include <boost/predef.h>
+
 #if defined(BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT)
 // Already defined.
 #elif defined(BOOST_LIBSTDCXX11)
@@ -18,16 +20,19 @@
 #if BOOST_LIBSTDCXX_VERSION > 40600
 #define BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT 1
 #endif
-#elif defined(_LIBCPP_VERSION)
+#elif BOOST_LIB_STD_CXX
 // https://github.com/llvm-mirror/libcxx/blob/release_30/include/utility#L206
-#if _LIBCPP_VERSION >= 3000
+#if BOOST_LIB_STD_CXX >= BOOST_VERSION_NUMBER(3, 0, 0)
 #define BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT 1
 #endif
-#elif defined(BOOST_MSVC)
+#elif defined(BOOST_LIB_STD_DINKUMWARE)
 // Apparently C++11 standard supported in Visual Studio 2012
 // https://msdn.microsoft.com/en-us/library/hh567368.aspx#stl
 // 2012 = VC+11 = BOOST_MSVC 1700 Hopefully!
-#if BOOST_MSVC >= 1700
+// I have no idea when Dinkumware added it, probably a lot
+// earlier than this check.
+#if BOOST_LIB_STD_DINKUMWARE >= BOOST_VERSION_NUMBER(6, 50, 0) ||              \
+  BOOST_COMP_MSVC >= BOOST_VERSION_NUMBER(17, 0, 0)
 #define BOOST_UNORDERED_HAVE_PIECEWISE_CONSTRUCT 1
 #endif
 #endif
diff --git a/include/boost/unordered/detail/implementation.hpp b/include/boost/unordered/detail/implementation.hpp
index fb1d4788..77d55b1d 100644
--- a/include/boost/unordered/detail/implementation.hpp
+++ b/include/boost/unordered/detail/implementation.hpp
@@ -17,7 +17,6 @@
 #include <boost/detail/select_type.hpp>
 #include <boost/limits.hpp>
 #include <boost/move/move.hpp>
-#include <boost/predef.h>
 #include <boost/preprocessor/arithmetic/inc.hpp>
 #include <boost/preprocessor/cat.hpp>
 #include <boost/preprocessor/repetition/enum.hpp>