Add throw_from_library_test

test/lib1_throw.cpp

@@ -0,0 +1,13 @@
+// Copyright 2018 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 "lib1_throw.hpp"
+
+void lib1::f()
+{
+    throw lib1::exception();
+}