Added thirdparty: boost library

thirdparty/include/boost/json/detail/ryu/ryu.hpp

@@ -0,0 +1,43 @@
+// Copyright 2018 Ulf Adams
+//
+// The contents of this file may be used under the terms of the Apache License,
+// Version 2.0.
+//
+//    (See accompanying file LICENSE-Apache or copy at
+//     http://www.apache.org/licenses/LICENSE-2.0)
+//
+// Alternatively, the contents of this file may be used under the terms of
+// the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE-Boost or copy at
+//     https://www.boost.org/LICENSE_1_0.txt)
+//
+// Unless required by applicable law or agreed to in writing, this software
+// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.
+
+/*
+    This is a derivative work
+*/
+
+#ifndef BOOST_JSON_DETAIL_RYU_HPP
+#define BOOST_JSON_DETAIL_RYU_HPP
+
+#include <boost/json/detail/config.hpp>
+
+namespace boost {
+namespace json {
+namespace detail {
+
+namespace ryu {
+
+BOOST_JSON_DECL
+int d2s_buffered_n(
+    double f, char* result, bool allow_infinity_and_nan = true) noexcept;
+
+} // ryu
+
+} // detail
+} // namespace json
+} // namespace boost
+
+#endif