message: Process: fixes exec()#  on UNIX
diff: @@ -132,6 +132,7 @@ Process::Process(
  char** argv = new char* [_args.size() + 1];
  for (size_t i = 0; i < _args.size(); ++i)
  argv[i] = const_cast<char*>(_args[i].c_str());
  + argv[_args.size()] = nullptr;
  for (auto&& [name, value] : _env)
  setenv(name.c_str(), value.c_str(), true);
  