Mirror Chooser for Devuan.

This little program allows the user to pick mirror, by choosing first a
country, then a mirror, or by manually entering mirror info.
The mirror list is built into it at compile time based on the canonical
Debian mirrors list, Mirrors.masterlist.

After it has run, the debconf question mirror/http/hostname will have
the mirror host, mirror/http/directory will have the base of the mirror,
and mirror/http/proxy may contain proxy info in standard form. These
are used by retrievers and by apt-setup.

The system for building the country list

1) get-iso-codes script
   Get ISO 3166 (country names) translations

 This needs the iso-codes package installed on the build machine

 The translations are picked from *.mo files by using msgunfmt utility and
 put into PO files in debian/iso-codes

2) mktemplates script
   Create the Choices lists in the templates file
   Insert translations in the templates file
   Create the translated templates file
 The Choices list are first grabbed from 
 Mirrors.masterlist (this file is refreshed at build time if possible).

 Then, the codes list is transformed into a country name list (in English)
 by using the iso_3166.tab file from the iso-codes package.

 This list is transformed into a comma-separated list (NOTE : country "names"
 may contain commas which need to be escaped) and inserted into the Choices
 lists in the templates file

 The translations (from debian/iso-codes/*po) and the "normal" translations
 of the remaining fields of the templates (from debian/po/*po) are merged
 together into PO files in debian/po-build

 The po2debconf utility inserts these translations into the templates

 To ensure the list of countries is sorted appropriatly for each language,
 this uses Indices-xx fields, which is a special debconf feature currently
 only implemented in cdebconf, the debconf flavour used in Debian Installer
 first stage.

The result is very sensitive to strange errors. For instance, one
common symptom during the early development of this script was Indices-xx
field not having all the same number of choices and not the same number of
choices than Choices-xx fields. When this happens, the multiselect
screen is completely *BROKEN* with "/dev/null" as the only choice..:-)

So, if this happens again, please look at the generated templates file
and count the number of Choices in each Indices fields and each Choices fields.