[c++0x patch] allow std::bind<void>

[Jonathan Wakely]

2009/12/24 Paolo Carlini:
>
> Jon, when you have the time, I think we have also another special case
> in <functional> which could be improved, maybe for std::function itself,
> please help me figuring out the details, I noticed this issue a lot of
> time ago. Anyway, I think the issue is that we don't have overloads /
> specializations for variadic functions: we catch elegantly any number of
> arguments with variadic templates but we don't catch variadic functions
> themselves. I think the std::is_function trait is already ok, however.

You mean old fashioned variadic "..." functions like printf?  Hmm, I
hadn't thought of that - I'll look into it.