dpkg-shlibdeps is too strict

[Stephane Bortzmeyer <bortzmeyer@pasteur.fr>]

When I create a package on my slink machine, it has the following dependencies:

 Depends: libc6 (>= 2.0.7u-6)

But the program does not use anything specific to that version and, if I 
install it (--force-depends) on a hamm system (libc6 2.0.7t), it runs fine.

This reall bothers me because I want the package to run on hamm without 
forcing users to upgrade to the slink's libc6.

I can change the dependency in control, but I would like to keep the 
advantages of ${shlibs:Depends} (for instance, the Alpha uses an other libc).

Reading dpkg-shlibdeps(1), I tried to use /etc/dpkg/shlibs.override and added:

libc 6         libc6 (>= 2.0.7t)

in it, but it gives now:

 Depends: libc6 (>= 2.0.7t), libc6 (>= 2.0.7u-6)