Bug#612099: apt-get install libc6:armel offers to install, should calculate removals

[Steve Langasek <vorlon@debian.org>]

Package: apt
Version: 0.8.3
Severity: normal

Configuring my system for multiarch, I see the following result when trying
to use apt-get:

$ sudo apt-get install libc6:armel
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  apt:armel apt-utils:armel coreutils:armel debconf:armel debconf-i18n:armel
  dpkg:armel findutils:armel gcc-4.5-base:armel gpgv:armel libacl1:armel
  libattr1:armel libbz2-1.0:armel libc-bin:armel libc6:armel libdb4.8:armel
  libgcc1:armel libgpm2:armel liblocale-gettext-perl:armel liblzma2:armel
  libncurses5:armel libreadline6:armel libselinux1:armel libstdc++6:armel
  libtext-charwidth-perl:armel libtext-iconv-perl:armel
  libtext-wrapi18n-perl:armel perl-base:armel readline-common:armel
  tzdata:armel ubuntu-keyring:armel xz-utils:armel zlib1g:armel
Suggested packages:
  aptitude:armel synaptic:armel wajig:armel bzip2:armel lzma:armel
  python-apt:armel debconf-doc:armel debconf-utils:armel
  libterm-readline-gnu-perl:armel libgnome2-perl:armel libnet-ldap-perl:armel
  mlocate:armel locate:armel slocate:armel gnupg:armel glibc-doc:armel
  gpm:armel
Recommended packages:
  gpg:armel
The following NEW packages will be installed:
  apt:armel apt-utils:armel coreutils:armel dpkg:armel findutils:armel
  gcc-4.5-base:armel gpgv:armel libacl1:armel libattr1:armel libbz2-1.0:armel
  libc-bin:armel libc6:armel libdb4.8:armel libgcc1:armel libgpm2:armel
  liblocale-gettext-perl:armel liblzma2:armel libncurses5:armel
  libreadline6:armel libselinux1:armel libstdc++6:armel
  libtext-charwidth-perl:armel libtext-iconv-perl:armel perl-base:armel
  xz-utils:armel zlib1g:armel
0 upgraded, 26 newly installed, 0 to remove and 36 not upgraded.
Need to get 14.7MB of archives.
After this operation, 46.0MB of additional disk space will be used.
Do you want to continue [Y/n]? 

But this libc6 package does not declare itself to be Multi-Arch: same, which
means that installing libc6:armel should *remove* libc6:amd64 *and all its
reverse dependencies*.  

So it's definitely a bug here that apt is not offering to remove my entire
system. :-)