Amends 7a7f2547f3, which added the triplet
including the script before the language_Territory name without it. The
truncate-from-the-end algorithm in QTranslator ended up trying the pure
language first, and - if found - ignored any more specific territory-
variant that might be present.
To fix this, replace the truncate-from-the-end algorithm when we try
to find files, and instead create a comprehensive list of fallbacks,
avoiding duplicates as we go along. Insert those fallbacks right after
their base-entry. We then try to find files for each entry, with and
without the prefix.
This fix is needed only in 6.8 and 6.5; from 6.9 onwards, the change to
QLocale::uiLanguages in 84afaafc9c6968dd76fcadc5392065d340543521 fixes
this on the correct level, making kludges in QTranslator unnecessary.
As a drive-by, replace int indices in for-loops with qsizetype.
Fixes: QTBUG-124898
Pick-to: 6.5
Change-Id: Ia3deceb4ed2c6ef5ca0a815cc7b8878bf29ef088
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
8c40e8cf12