Newer Linux kernels would return EINVAL instead of ENOENT.
The patch below, taken from Gnulib, allows the test to pass when
these Linux versions are in use:
https://lists.gnu.org/archive/html/bug-gnulib/2011-03/msg00308.html .

diff --git a/tests/test-readlink.h b/tests/test-readlink.h
index 08d5662..7247fc4 100644
--- a/tests/test-readlink.h
+++ b/tests/test-readlink.h
@@ -38,7 +38,7 @@ test_readlink (ssize_t (*func) (char const *, char *, size_t), bool print)
   ASSERT (errno == ENOENT);
   errno = 0;
   ASSERT (func ("", buf, sizeof buf) == -1);
-  ASSERT (errno == ENOENT);
+  ASSERT (errno == ENOENT || errno == EINVAL);
   errno = 0;
   ASSERT (func (".", buf, sizeof buf) == -1);
   ASSERT (errno == EINVAL);
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<tr><td><span title='2020-06-24 20:24:34 +0200'>2020-06-24</span></td><td><a href='/guix/commit/gnu/image.scm?id=b904b59ce592c89dfb4675a8c06757afed6738a0'>image: Move hurd image definition to a dedicated file.</a><span class='msg-avail'>...</span></td><td>Mathieu Othacehe</td></tr>
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<tr><td><span title='2020-05-05 16:13:53 +0200'>2020-05-05</span></td><td><a href='/guix/commit/gnu/image.scm?id=f19cf27c2b9ff92e2c0fd931ef7fde39c376adaa'>image: Add a new API.</a><span class='msg-avail'>...</span></td><td>Mathieu Othacehe</td></tr>