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

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

@@ -0,0 +1,53 @@
+/*!
+@file
+Forward declares `boost::hana::intersection`.
+
+@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_INTERSECTION_HPP
+#define BOOST_HANA_FWD_INTERSECTION_HPP
+
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/when.hpp>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    //! Returns the intersection of two sets.
+    //! @relates hana::set
+    //!
+    //! Given two sets `xs` and `ys`, `intersection(xs, ys)` is a new set
+    //! containing exactly those elements that are present both in `xs` and
+    //! in `ys`. In other words, the following holds for any object `x`:
+    //! @code
+    //!     x ^in^ intersection(xs, ys) if and only if x ^in^ xs && x ^in^ ys
+    //! @endcode
+    //!
+    //!
+    //! @param xs, ys
+    //! Two sets to intersect.
+    //!
+    //!
+    //! Example
+    //! -------
+    //! @include example/intersection.cpp
+#ifdef BOOST_HANA_DOXYGEN_INVOKED
+    constexpr auto intersection = [](auto&& xs, auto&& ys) {
+        return tag-dispatched;
+    };
+#else
+    template <typename S, typename = void>
+    struct intersection_impl : intersection_impl<S, when<true>> { };
+
+    struct intersection_t {
+        template <typename Xs, typename Ys>
+        constexpr auto operator()(Xs&& xs, Ys&& ys) const;
+    };
+
+    constexpr intersection_t intersection{};
+#endif
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_FWD_INTERSECTION_HPP