- Update to 3.20
* debian-specific change only
- includes 3.19
* Fix lintian warnings.
- includes 3.18
* Make sure memory is initialized to zero before attempting to
read hostname.
- includes 3.17
* Use _GNU_SOURCE feature test macro, instead of glibc internal
__USE_GNU.
* Use getdomainname instead of yp_get_default_domain because it
is more widely available and avoids the -lnsl dependency.
* localnisdomain is kept, even though it should be the same as
localdomain, so the behaviour is not changed in case of an error.
* Replace 'dh-clean -k' with 'dh-prep'
- cleanup with spec-cleaner