test-readlink failure on GNU/Linux

[Ludovic Courtès]

Hello,

‘test-readlink’ from GNU M4 1.4.16 fails on GNU/Linux with Linux 3.0.4
and GNU libc 2.13 with an assertion failure at test-readlink.h:41:

    40: ASSERT (func ("", buf, sizeof buf) == -1);
    41: ASSERT (errno == ENOENT);

It turns out that errno is set to EINVAL instead of ENOENT, which is
indeed not what POSIX suggests [0].

Thoughts?

Thanks,
Ludo’.

[0] From
    <http://pubs.opengroup.org/onlinepubs/9699919799/functions/readlink.html>,
    EINVAL means that the “path argument names a file that is not a
    symbolic link.”