Isolated emscripten in new lib

lib/emscripten/emtests/test_em_asm_parameter_pack.cpp

@@ -0,0 +1,22 @@
+// Copyright 2017 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 <emscripten.h>
+template <typename... Args>
+int call(Args... args) {
+  return(EM_ASM_INT(
+    {
+      out(Array.prototype.join.call(arguments, ','));
+    },
+    args...
+  ));
+}
+
+int main(int argc, char **argv) {
+  call(1);
+  call(1, 2);
+  call(1, 2, 3);
+  return 0;
+}