boost::nowide::cerr is buffered

[Flamefire]

When using std::cerr << "Something\n" it behaves the same as std::cerr << "Something" << std::endl, i.e. any output is directly flushed/printed to the console.

However there is some buffering happening such that if the application crashes or otherwise terminates it is not ensured that the output is/was actually visible.

Investigate that e.g. the following holds:

Once initialized, (std::cerr.flags() & unitbuf) != 0 (same for std::wcerr) meaning that any output sent to these stream objects is immediately flushed to the OS (via [std::basic_ostream::sentry](https://en.cppreference.com/w/cpp/io/basic_ostream/sentry)'s destructor).

In addition, std::cerr.tie() returns &[std::cout](http://en.cppreference.com/w/cpp/io/cout) (same for std::wcerr and [std::wcout](https://en.cppreference.com/w/cpp/io/cout)), meaning that any output operation on std::cerr first executes [std::cout](http://en.cppreference.com/w/cpp/io/cout).flush() (via [std::basic_ostream::sentry](https://en.cppreference.com/w/cpp/io/basic_ostream/sentry)'s constructor).

[Flamefire]

This has been fixed for Boost 1.77 / Nowide 11.2 by 4ac0ca5