Relocate piecewise_construct to impl file, remove unnecessary fwd header

include/boost/unordered/detail/fwd.hpp

@@ -1,46 +0,0 @@
-
-// Copyright (C) 2008-2016 Daniel James.
-// Copyright (C) 2022 Christian Mazakas
-// Distributed under the Boost Software License, Version 1.0. (See accompanying
-// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-
-#ifndef BOOST_UNORDERED_FWD_HPP_INCLUDED
-#define BOOST_UNORDERED_FWD_HPP_INCLUDED
-
-#include <boost/config.hpp>
-#if defined(BOOST_HAS_PRAGMA_ONCE)
-#pragma once
-#endif
-
-#include <boost/predef.h>
-
-#include <utility>
-#include <tuple>
-
-////////////////////////////////////////////////////////////////////////////////
-// Configuration
-//
-// Unless documented elsewhere these configuration macros should be considered
-// an implementation detail, I'll try not to break them, but you never know.
-
-// Use Sun C++ workarounds
-// I'm not sure which versions of the compiler require these workarounds, so
-// I'm just using them of everything older than the current test compilers
-// (as of May 2017).
-
-#if !defined(BOOST_UNORDERED_SUN_WORKAROUNDS1)
-#if BOOST_COMP_SUNPRO && BOOST_COMP_SUNPRO < BOOST_VERSION_NUMBER(5, 20, 0)
-#define BOOST_UNORDERED_SUN_WORKAROUNDS1 1
-#else
-#define BOOST_UNORDERED_SUN_WORKAROUNDS1 0
-#endif
-#endif
-
-namespace boost {
-  namespace unordered {
-    using std::piecewise_construct;
-    using std::piecewise_construct_t;
-  } // namespace unordered
-} // namespace boost
-
-#endif

include/boost/unordered/detail/implementation.hpp

@@ -15,7 +15,6 @@
 #endif
 
 #include <boost/unordered/detail/fca.hpp>
-#include <boost/unordered/detail/fwd.hpp>
 #include <boost/unordered/detail/opt_storage.hpp>
 #include <boost/unordered/detail/serialize_tracked_address.hpp>
 #include <boost/unordered/detail/static_assert.hpp>
@@ -80,6 +79,10 @@ namespace boost {
 
 namespace boost {
   namespace unordered {
+
+    using std::piecewise_construct;
+    using std::piecewise_construct_t;
+
     namespace detail {
 
       template <typename Types> struct table;