add boost on mac

macx64/include/boost/hof/detail/forward.hpp

@@ -0,0 +1,37 @@
+/*=============================================================================
+    Copyright (c) 2014 Paul Fultz II
+    forward.h
+    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_HOF_GUARD_FORWARD_H
+#define BOOST_HOF_GUARD_FORWARD_H
+
+#include <utility>
+
+namespace boost { namespace hof {
+
+// contexpr-friendly forwarding
+
+template<typename T>
+constexpr T&& forward(typename std::remove_reference<T>::type& t) noexcept
+{ return static_cast<T&&>(t); }
+
+
+template<typename T>
+constexpr T&& forward(typename std::remove_reference<T>::type&& t) noexcept
+{
+  static_assert(!std::is_lvalue_reference<T>::value, "T must not be an lvalue reference type");
+  return static_cast<T&&>(t);
+}
+
+#if (defined(__GNUC__) && !defined (__clang__) && __GNUC__ == 4 && __GNUC_MINOR__ < 7) || defined(_MSC_VER)
+#define BOOST_HOF_FORWARD(...) boost::hof::forward<__VA_ARGS__>
+#else
+#define BOOST_HOF_FORWARD(...) static_cast<__VA_ARGS__ &&>
+#endif
+
+}} // namespace boost::hof
+
+#endif