It was previously calling setlocale(), which makes no difference to
the Unix backend for the system locale, since that's based on
environment variables (that would normally be used to get default
values for the various setlocale() categories, but only the first time
each is asked for). So, on Unix, set the environment variable, too.
It's also necessary to instantiate a QSystemLocale instance
transiently to trigger a refresh of the system locale data.
Pick-to: 6.2
Change-Id: If92e44053f9021e96c814f4b289f4fadaa7027e0
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
e300fc9204