Incomplete work for using Boost.Polygon to compute medial axis

xs/src/boost/smart_ptr/detail/sp_nullptr_t.hpp

@@ -0,0 +1,45 @@
+#ifndef BOOST_SMART_PTR_DETAIL_SP_NULLPTR_T_HPP_INCLUDED
+#define BOOST_SMART_PTR_DETAIL_SP_NULLPTR_T_HPP_INCLUDED
+
+// MS compatible compilers support #pragma once
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
+#endif
+
+//  detail/sp_nullptr_t.hpp
+//
+//  Copyright 2013 Peter Dimov
+//
+//  Distributed under the Boost Software License, Version 1.0.
+//  See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config.hpp>
+#include <cstddef>
+
+#if !defined( BOOST_NO_CXX11_NULLPTR )
+
+namespace boost
+{
+
+namespace detail
+{
+
+#if defined( __clang__ ) && !defined( _LIBCPP_VERSION ) && !defined( BOOST_NO_CXX11_DECLTYPE )
+
+    typedef decltype(nullptr) sp_nullptr_t;
+
+#else
+
+    typedef std::nullptr_t sp_nullptr_t;
+
+#endif
+
+} // namespace detail
+
+} // namespace boost
+
+#endif // !defined( BOOST_NO_CXX11_NULLPTR )
+
+#endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_NULLPTR_T_HPP_INCLUDED