Bug#988301: exim :include: not working after jessie

[Josip Rodin]

Package: exim4
Version: 4.89-2+deb9u8

Hi,

After an upgrade to stretch, and likewise buster, the :include:
functionality of the redirect router seems to be broken.

I have include_directory set to /etc/exim4, and a subdirectory with
files containing alias content, an an aliases file containing e.g.:

priprema: :include:/etc/exim4/dynaliases/priprema

This worked perfectly up to jessie, but after the upgrade, deliveries
started choking with messages like:

R=aliases defer (-17): error in redirect data: failed to open
/etc/exim4/dynaliases/priprema (component of included file); could
be symbolic link

strace shows:

openat(AT_FDCWD, "/etc/exim4/dynaliases", O_RDONLY|O_LARGEFILE) = 7
openat(7, "/priprema", O_RDONLY|O_LARGEFILE|O_NOFOLLOW) = -1 ENOENT (No such file or directory)

Obviously it's supposed to continue to find the file in that directory,
because the file hasn't been touched...

Am I missing something here?

A diff between 4.84 and 4.89 sources shows that this code was changed
inbetween, with a block of new code using EXIM_HAVE_OPENAT replacing
the old logic...?

Please fix it. TIA.

-- 
Josip Rodin