[boost] [result_of] Make `cpp0x_result_of_impl` public

Subject: [boost] [result_of] Make `cpp0x_result_of_impl` public
From: Michel Morin (mimomorin_at_[hidden])
Date: 2012-03-24 04:52:06

There are two implementations of boost::result_of: a TR1-style
implementation and a decltype-based implementation. While
the TR1-style implementation has a public interface `boost::tr1_result_of`,
decltype-based one doesn't have a public interface.

By defining BOOST_RESULT_OF_USE_DECLTYPE,
boost::result_of use decltype-based implementation.
But this is not always a viable solution, since this breaks
some Boost libraries.

So how about adding `boost::cxx11_result_of` as public interface
of the decltype-based implementation?
Attached a patch to add `boost::cxx11_result_of`.
(This patch also changes the name of `cpp0x_result_of_impl`
to `cxx11_result_of_impl` to reflect the recent discussion on
the cpp/cxx naming.)

P.S.
Is it worth trying to use this `boost::cxx11_result_of`
in `boost::transform_iterator` code on trunk?

Regards,
Michel