In order to create or update a translatable file, run the following
command in the directory po/:

./update.sh xx

where xx is the two-letter language code according to ISO 639 (which,
if needed, may be suffixed by a country code according to ISO 3166).
Quassel will automatically load these translation files based on the
system locale. Examples for valid codes: de, en_US

You can open translation files with poedit for example and add/edit
translated strings.

The *.po files can and should be kept in sync with the source code by
running update.sh regularly (existing translations won't be removed).

NOTE: Remember to remove X-Virgin-Header line if you want to preserve
your header.

Qt itself does not use the *.po files, but a compact binary format
(*.qm). These files will automatically be generated at build time. By
default, all languages will be built. To select languages, use
environment variable LINGUAS to specify superset of languages you want
to build in. As you can see in example there we will build only Czech
German and French translations.

EXAMPLE:
$ export LINGUAS="cs de fr"
$ cmake /path/to/source

NOTE: You'll need lupdate, lconvert, lrelease installed with your Qt in
      order to generate translation files. Some distributions don't
      package that tool; in that case you won't get translations.

The .pot file is regenerated using `./update-pot.sh` and can be pushed
to Transifex via `tx push -s`.
Note that as of Feb 2016 this is done automatically by nightly runs of
scripts/tx-sync.sh which pushes an updated quassel.pot to a location
that is fetched by Transifex on regular intervals. This location is
currently configured as
<https://github.com/quassel/quassel-i18n/raw/tx-sync/po/quassel.pot> and
can be updated at https://www.transifex.com/quassel/quassel/content/ →
"Auto update resources".