long paths not supported on windows for rename, getFileStatus

[joeyh]

System.PosixCompat.Files.rename will fail if a filename is longer than 285 characters or so, which is a default limit in Windows.

This is because it uses moveFileEx from Win32, and Win32 is a direct mapping to the win32 api. However, the problem could be avoided if the path were converted to "UNC-style" first. That conversion is how ghc is generally supporting long filenames on windows.

One easy fix would be to depend on directory-1.3.9.0 and use renamePath instead of moveFileEx. It so happens that renamePath does do UNC-style conversion, before passing it off to Win32.

(There are probably some other functions that also don't support long filenames.)

[joeyh]

getFileStatus is another function from unix-compat that does not support long filenames. It's using createFile from Win32. Doing UNC-style conversion in getFileStatus would avoid this portability land-mine.