mingw: Create directory/file symlink from information available
Windows NTFS symbolic links require specifying whether the target is a file or
directory at creation time. This can partially be done by interrogating the
filesystem, however when creating symbolic links that are within a repository,
there can be no guarantee of the order of creation.
This patch enables the code to allow interrogation of the git cache to determine
whether a target will be a file or a directory.
Signed-off-by: Michael Geddes <michael@frog.wheelycreek.net>