Isolated emscripten in new lib

lib/emscripten/emtests/test_exceptions_resume.cpp

@@ -0,0 +1,73 @@
+// 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.
+
+#include <stdio.h>
+#include <string>
+#include <typeinfo>
+#include <stdexcept>
+
+using namespace std;
+
+class MathError: public std::runtime_error {
+    public:
+        explicit MathError(const std::string& what) : std::runtime_error(what) { }
+};
+
+std::string _latest_err_msg;
+int _result;
+
+int cpp_adder(int a, int b)
+{
+  if (a < b)
+    throw MathError ("a cannot be less than b.");
+
+  return a + b;
+}
+
+extern "C" {
+
+  const char* latest_err_msg() {
+    return _latest_err_msg.c_str();
+  }
+
+  int result() { return _result; }
+
+  int c_adder(int a, int b)
+  {
+/*_1*/  try {
+/*_2*/      try {
+/*_3*/          try {
+                _result = cpp_adder(a, b);
+/*+3a*/         } catch (MathError& e) {
+                if (string(e.what()).find("not-found-here") == string::npos)
+                    throw MathError(string("Special exception caught: ") + typeid(e).name() + ": " + e.what());
+                else
+                    throw;
+/*+3b*/         } catch (exception& e) {
+                throw;
+            }
+/*+2*/      } catch (exception& e) {
+            throw;
+        }
+        return 0;
+/*+1*/  } catch (exception& e) {
+        _latest_err_msg = string(typeid(e).name()) + ": " + e.what();
+        return 1;
+    }
+  }
+}
+
+int main() {
+  int rc;
+
+  rc = c_adder(20, 35);
+  if (rc == 0)
+    printf("2nd call, result = %d\n", result());
+  else
+    printf("2nd call, sadface: %s\n", latest_err_msg());
+
+  return 0;
+}
+