https://lists.gnu.org/archive/html/bug-gnulib/2012-02/msg00038.html
detailed a couple of bugs in gnulib's canonicalize that were visible
through coreutils' readlink, but only on systems where // is distinct
from /. This particular test assumes the POSIX fix which requires
canonicalization of a symlink containing just slashes to behave as
if slashes separating the symlink from the rest of the name are
elided (see http://austingroupbugs.net/view.php?id=541), as that is
the only useful (and current) behavior on Cygwin. That is,
ln -s / root
ls root/dev
must list the contents of /dev, not //dev.
* tests/misc/readlink-root: New test.
* tests/Makefile.am (TESTS): Run it.
