Add boost/system/error_category.hpp

include/boost/system/error_category.hpp

@@ -0,0 +1,13 @@
+#ifndef BOOST_SYSTEM_ERROR_CATEGORY_HPP_INCLUDED
+#define BOOST_SYSTEM_ERROR_CATEGORY_HPP_INCLUDED
+
+// Copyright 2020 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0
+// http://www.boost.org/LICENSE_1_0.txt
+//
+// See library home page at http://www.boost.org/libs/system
+
+#include <boost/system/detail/error_category.hpp>
+#include <boost/system/detail/error_category_impl.hpp>
+
+#endif // #ifndef BOOST_SYSTEM_ERROR_CATEGORY_HPP_INCLUDED