Add sp_warning_test

test/Jamfile

@@ -359,3 +359,5 @@ run wp_guides_test.cpp ;
 
 compile-fail shared_from_fail.cpp ;
 compile-fail weak_from_fail.cpp ;
+
+compile sp_warning_test.cpp ;

test/sp_warning_test.cpp

@@ -0,0 +1,13 @@
+// Copyright 2020 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ >= 5
+# pragma GCC diagnostic error "-Wsuggest-override"
+#endif
+
+#include <boost/smart_ptr.hpp>
+
+int main()
+{
+}