[#522] Patch by Franck Villaume to fix behaviour of mailing lists in Debian
prepare 5.1.2
make this a bit more legible and fix one case of indentation
SECURITY: do not make homedir archives of deleted users world-readable
improve compression ratio
deleted unix accounts are 'D', not 'N', just like regular statūs
Allow planning tasks up to 2038
Hand-merge from 5.1: fixes to Unix accounts and Debian-specific script
Contentless merge from 5.1