Isolated emscripten in new lib

lib/emscripten/emtests/test_exceptions_multiple_inherit_rethrow.cpp

@@ -0,0 +1,46 @@
+// Copyright 2018 The Emscripten Authors.  All rights reserved.
+// Emscripten is available under two separate licenses, the MIT license and the
+// University of Illinois/NCSA Open Source License.  Both these licenses can be
+// found in the LICENSE file.
+
+#include <iostream>
+
+struct base_1
+{
+    std::string v;
+};
+
+struct base_2
+{
+    std::string v;
+};
+
+struct derived : base_1, base_2
+{
+    derived()
+    {
+        base_1::v = "a";
+        base_2::v = "b";
+    }
+};
+
+int main()
+{
+    try
+    {
+        throw derived();
+    }
+    catch (const base_2&)
+    {
+        try
+        {
+            std::rethrow_exception(std::current_exception());
+        }
+        catch (const base_1& ex)
+        {
+            std::cout << ex.v << std::endl;
+        }
+    }
+
+    return 0;
+}