stabilize build system: depends, installer, boost/bdb fixes, cross targets groundwork

depends/x86_64-pc-linux-gnu/include/boost/hana/accessors.hpp

@@ -0,0 +1,56 @@
+/*!
+@file
+Defines `boost::hana::accessors`.
+
+@copyright Louis Dionne 2013-2017
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#ifndef BOOST_HANA_ACCESSORS_HPP
+#define BOOST_HANA_ACCESSORS_HPP
+
+#include <boost/hana/fwd/accessors.hpp>
+
+#include <boost/hana/concept/struct.hpp>
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/dispatch.hpp>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    template <typename S>
+    struct accessors_t {
+    #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
+        static_assert(hana::Struct<S>::value,
+        "hana::accessors<S> requires 'S' to be a Struct");
+    #endif
+
+        constexpr decltype(auto) operator()() const {
+            using Accessors = BOOST_HANA_DISPATCH_IF(accessors_impl<S>,
+                hana::Struct<S>::value
+            );
+
+            return Accessors::apply();
+        }
+    };
+
+    template <typename S, bool condition>
+    struct accessors_impl<S, when<condition>> : default_ {
+        template <typename ...Args>
+        static constexpr auto apply(Args&& ...) = delete;
+    };
+
+    namespace struct_detail {
+        template <typename ...>
+        struct is_valid { static constexpr bool value = true; };
+    }
+
+    template <typename S>
+    struct accessors_impl<S, when<
+        struct_detail::is_valid<typename S::hana_accessors_impl>::value
+    >>
+        : S::hana_accessors_impl
+    { };
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_ACCESSORS_HPP