If the user tries to clone a Git repository that is actually a
workdir of another repository (by way of contrib git-new-workdir)
then the contents of .git is a series of Windows .lnk files which
Tcl can't read if this is a native Tcl process. To read the real
objects directory we need to resolve the link to that location.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>