Isolated emscripten in new lib

lib/emscripten/emtests/test_exceptions_primary.cpp

@@ -0,0 +1,29 @@
+// Copyright 2014 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.
+
+// exception_ptr example
+#include <iostream>       // std::cout
+#include <exception>      // std::exception_ptr, std::current_exception, std::rethrow_exception
+#include <stdexcept>      // std::logic_error
+
+int main () {
+  std::exception_ptr p;
+  try {
+     throw std::logic_error("some logic_error exception");   // throws
+  } catch(const std::exception& e) {
+     p = std::current_exception();
+     std::cout << "exception caught, but continuing...\n";
+  }
+
+  std::cout << "(after exception)\n";
+
+  try {
+     std::rethrow_exception (p);
+  } catch (const std::exception& e) {
+     std::cout << "exception caught: " << e.what() << '\n';
+  }
+  return 0;
+}
+