apt-0.5.15lorg2-alt31 provides better possibilities for e.g.
checking if every single package in the repo can be installed
on top of basesystem.

$ hsh --init --no-stuff --pkg-build-list=basesystem
...
$ time ./build/aptbox/apt-get -qq --dry-run script ./installable.lua
cannot install: libsundance-devel
cannot install: branding-altlinux-workbench-kde3-settings
cannot install: libtrilinos-new_package-devel-static
cannot install: libsundance-devel-static
cannot install: libtrilinos-devel
cannot install: kile
cannot install: libtrilinos-devel-static
./build/aptbox/apt-get -qq --dry-run script ./installable.lua  317.24s user 1.54s system 97% cpu 5:26.02 total
$

This check should ultimately replace our check for unmet dependencies
in girar-builder.  Especially if I manage to make it even faster.