Add system_category.hpp

test/Jamfile.v2

@@ -81,3 +81,4 @@ run error_category_test2.cpp ;
 run error_condition_test.cpp ;
 run error_condition_test2.cpp ;
 run generic_category_test2.cpp ;
+run system_category_test2.cpp ;

test/system_category_test2.cpp

@@ -0,0 +1,21 @@
+// Copyright 2020 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0
+// http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/system/system_category.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <cstring>
+
+// Tests whether system_category() is functional when only
+// system_category.hpp is included
+
+namespace sys = boost::system;
+
+int main()
+{
+    sys::error_category const & cat = sys::system_category();
+
+    BOOST_TEST_CSTR_EQ( cat.name(), "system" );
+
+    return boost::report_errors();
+}