Currently annex.thin needs hard link support to be efficient;
it hard links the content from .git/annex/objects into the work tree.
When hard links are not supported, two copies of checked out files exist on
disk.

Would it be possible to make it work w/o hard links? Note that direct mode
does avoid two copies of files.

IIRC the main reason for the hard link is so, when git checkout deletes a
work tree file, the only copy of the file is not lost. Seems this would
need a git hook run before checkout to rescue such files.

Also some parts of git-annex's code, including `withObjectLoc`, assume
that the .annex/objects is present, and so it would need to be changed
to look at the work tree file. --[[Joey]]