Attn: Maintainer of boost/bind.hpp

From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2019-12-13 16:47:29

In boost/bind.hpp there is injection of a boost namespace contents into
the global namespace:

```c++
#include <boost/bind/bind.hpp>

#ifndef BOOST_BIND_NO_PLACEHOLDERS

#if defined(BOOST_CLANG)
# pragma clang diagnostic push
# if  __has_warning("-Wheader-hygiene")
#  pragma clang diagnostic ignored "-Wheader-hygiene"
# endif
#endif

using namespace boost::placeholders;

#if defined(BOOST_CLANG)
# pragma clang diagnostic pop
#endif

#endif // #ifndef BOOST_BIND_NO_PLACEHOLDERS
```

The fact that Boost actually disables the relevant compiler warning
makes this particularly insidious.

No modern C++ library should ever do "using namespace" into the global
namespace in its public headers. Please fix this in the next release of
Boost.

Niall