Import of Asio to pkgsrc-wip.
This is not Boost.Asio this is the non-Boost Asio even thou it
requires Boost when used with a compiler that does not support c++11.
Boost.Asio is included in Boost.


Asio is a cross-platform C++ library for network and low-level I/O
programming that provides developers with a consistent asynchronous
model using a modern C++ approach.
Forgot TODO.