moving archdetect functionality to libd-i

[Colin Watson <cjwatson@debian.org>]

I've been playing around with a .deb of kbd-chooser for a project at
work [1]. kbd-chooser calls out to archdetect to figure out the
subarchitecture, and modifies its behaviour based on that, so I need to
have an archdetect equivalent in the installed system. I don't like the
idea of creating yet another .deb just for this, though.

The situation seems pretty similar to that of mapdevfs: we have the guts
in libdebian-installer, and a stub program wrapping those guts. Plus, in
this case, there's no size issue with moving things into libd-i because
every image that contains libd-i also contains archdetect.

Thus, I'd like to move most of archdetect from ddetect to libd-i, and
expose a di_subarchitecture() or similar symbol there; this would also
allow us to avoid at least two grotty popen() calls (anna and
kbd-chooser). Any objections?

[1] http://udu.wiki.ubuntu.com/OEMInstaller

Thanks,

-- 
Colin Watson                                       [cjwatson@debian.org]