message: workaround xl-16 compiler bug(?)
  I think that using new style initialization {} is legal in this context,
  but I might be wrong. Let's see whether the compiler is happier with the
  alternate style.
diff: @@ -206,7 +206,7 @@ int process_unused_args(adios2sys::CommandLineArguments &arg)
  arg.GetUnusedArguments(&nuargs, &uargs);
  std::vector<char *> retry_args;
  - retry_args.push_back(new char[4]{});
  + retry_args.push_back(new char[4]());
  // first arg is argv[0], so skip that
  for (int i = 1; i < nuargs; i++)
  