symlinks

[Paul Eggert]

Unfortunately that code won't work if toname is of the form FOO/BAR,
where FOO is a symbolic link to some other place in the filesystem.

The simplest fix is to remove the HAVE_SYMLINK code entirely, and to
fail if the hard-link call fails.  It's one less thing to configure in
Makefile and in private.h.  But if you want to support situations
where hard links don't work, I think it would be simpler and more
portable to make a copy instead of a link.