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

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

@@ -0,0 +1,50 @@
+/*!
+@file
+Forward declares `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_FWD_ACCESSORS_HPP
+#define BOOST_HANA_FWD_ACCESSORS_HPP
+
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/when.hpp>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    //! Returns a `Sequence` of pairs representing the accessors of the
+    //! data structure.
+    //! @ingroup group-Struct
+    //!
+    //! Given a `Struct` `S`, `accessors<S>()` is a `Sequence` of `Product`s
+    //! where the first element of each pair is the "name" of a member of
+    //! the `Struct`, and the second element of each pair is a function that
+    //! can be used to access that member when given an object of the proper
+    //! data type. As described in the global documentation for `Struct`, the
+    //! accessor functions in this sequence must be move-independent.
+    //!
+    //!
+    //! Example
+    //! -------
+    //! @include example/accessors.cpp
+#ifdef BOOST_HANA_DOXYGEN_INVOKED
+    template <typename S>
+    constexpr auto accessors = []() {
+        return tag-dispatched;
+    };
+#else
+    template <typename S, typename = void>
+    struct accessors_impl : accessors_impl<S, when<true>> { };
+
+    template <typename S>
+    struct accessors_t;
+
+    template <typename S>
+    constexpr accessors_t<S> accessors{};
+#endif
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_FWD_ACCESSORS_HPP