[filesystem] Wave regression test failure on Mingw

[rwebb <richard.webb@…>]

One of the Wave regression tests is failing On Mingw with the error

../boost/filesystem/v2/operations.hpp:1191:24: error: 'boost::filesystem2::create_hard_link' has not been declared

(see ​http://tinyurl.com/3x3y9jj).

Looks like the "using filesystem2::create_hard_link;" on line 1191 of operations.hpp needs to be guarded with an

#if !defined(BOOST_WINDOWS_API) || defined(BOOST_FS_HARD_LINK)

as the declaration of create_hard_link iteself is.

[jim@…]

This change is also required for a MinGW-32 project just upgraded from boost 1.38. Thanks for doing the research.

[Beman Dawes]

Fixed by changeset 65371. See #4487.