New cdebconf facility allowing simpler translated choices

[Colin Watson <cjwatson@debian.org>]

I've added this feature to cdebconf in trunk:

  * Allow Choices-C to be listed separately from Choices (etc.) in templates
    files. This lets you say "Choices: ${CHOICES-TRANS}" and "Choices-C:
    ${CHOICES}" to substitute reliably into translated and untranslated
    templates without having to ensure that ${CHOICES-TRANS} is translated
    to the same thing in every language.

(Note that this will not be available until cdebconf 0.106 is built and
daily initrd builds are refreshed to include it.)

To take an example, here's a template from kbd-chooser:

  Template: console-tools/archs
  Type: select
  # Translators, always translate with ${KBD-ARCHS-L10N}
  _Choices: ${KBD-ARCHS}
  _Description: Type of keyboard:
   Please choose the type of keyboard to configure.

In practice, this is unreliable: translators don't always manage 100%
accuracy on preserving the specified translated text, and we have to go
around fixing things up afterwards (see e.g. r40291). Also, all the
Choices-* fields take up valuable space. With cdebconf 0.106, you can do
the following instead:

  Template: console-tools/archs
  Type: select
  Choices-C: ${KBD-ARCHS}
  Choices: ${KBD-ARCHS-L10N}
  _Description: Type of keyboard:
   Please choose the type of keyboard to configure.

(This will cause a lintian warning at present, but that will be fixed in
lintian 1.23.25.)

Please let me know about any problems caused by this; I don't always
reliably keep up with debian-boot, so it might be worth poking me on
IRC.

Cheers,

-- 
Colin Watson                                       [cjwatson@debian.org]