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

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

@@ -0,0 +1,50 @@
+/*!
+@file
+Forward declares `boost::hana::is_disjoint`.
+
+@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_IS_DISJOINT_HPP
+#define BOOST_HANA_FWD_IS_DISJOINT_HPP
+
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/when.hpp>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    //! Returns whether two `Searchable`s are disjoint.
+    //! @ingroup group-Searchable
+    //!
+    //! Given two `Searchable`s `xs` and `ys`, `is_disjoint` returns a
+    //! `Logical` representing whether the keys in `xs` are disjoint from
+    //! the keys in `ys`, i.e. whether both structures have no keys in common.
+    //!
+    //!
+    //! @param xs, ys
+    //! Two `Searchable`s to test for disjointness.
+    //!
+    //!
+    //! Example
+    //! -------
+    //! @include example/is_disjoint.cpp
+#ifdef BOOST_HANA_DOXYGEN_INVOKED
+    constexpr auto is_disjoint = [](auto const& xs, auto const& ys) {
+        return tag-dispatched;
+    };
+#else
+    template <typename S1, typename S2, typename = void>
+    struct is_disjoint_impl : is_disjoint_impl<S1, S2, when<true>> { };
+
+    struct is_disjoint_t {
+        template <typename Xs, typename Ys>
+        constexpr auto operator()(Xs&& xs, Ys&& ys) const;
+    };
+
+    constexpr is_disjoint_t is_disjoint{};
+#endif
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_FWD_IS_DISJOINT_HPP