Filesystem Files

Changes:

• Pull request #163, build support for Haiku (also fixes #159)
• Pull request #162, fix for directory iterator treating all files subsequent to a symlink as symlink on Windows
• Pull request #161, the CMake alias ghcFilesystem::ghc_filesystem is now set unconditionally
• Fix for #160, the cmake config now only sets install targets by default if the project is no subproject, as documented
• Fix for #157, suppress C4191 warning on MSVC for GetProcAddress casts
• Fix for #156, on POSIX stem(), filename() and extension() of fs::path would return wrong result if a colon was in the filename
• Pull request #154, build support for GNU/Hurd
• Pull request #153, fixed fs::last_write_time(path, time, ec) setter on iOS, tvOS and watchOS
• Fix for #151, fs::directory_entry::refresh() now, consistently with status() will not throw on symlinks to non-existing targets, but make the entry have file_type::not_found as the type
• Pull request #149, add version to CMake project and export it
• Fix for #146, handle EINTR on POSIX directory iteration and file copy to avoid errors on network filesystems
• Pull request #145, fix for Y2038 bug in timeToFILETIME on Windows
• Pull request #144, fs::copy_file() now also copies the permissions
• Pull request #143, fix for fs::copy_file() ignoring the skip_existing option.

Thank you to all the reporters of issues and contributors of PRs!