C++11 compliance: Add ArgTypes to packaged_task template

[viboes]

The following should be taken in account

    template<class R, class... ArgTypes>
    class packaged_task<R(ArgTypes...)> {
    public:
// execution
      void operator()(ArgTypes... );
      void make_ready_at_thread_exit(ArgTypes...);

[viboes]

Unfortunately this breaks the current interface. I will add it for version 4. If variadic templates are not available only the signature R() will be provided

    template<class R>
    class packaged_task<R()> {
    public:
      void operator()();

[viboes]

Committed in trunk [80755].

[viboes]

Committed revision [81667].