Since Perl 5.28, Perl has used the thread-safe uselocale() functions
from the C standard library when setting the locale. Once a thread-safe
locale setting has been made, the Locale::gettext functions will use
those settings, not the global locale settings. So calling the drakx
c::setlocale() and c::init_setlocale() functions, which still use the
underlying setlocale() function from the C standard library normally
has no effect. However, prior to Perl 5.38, there was a bug in Perl
that could cause the main thread to revert to using the global locale
settings, and it it would seem this bug was being triggered by the
stage2 installer, meaning it still properly translated the UI after
the language selection step. Now we have a newer version of Perl, this
is no longer so, and the UI contiues to be in English after the user
has selected a different language (mga#34656).
The POSIX::setlocale() function affects the thread-safe locale, so can
be used to fix this bug.
This patch removes the c::setlocale() function to prevent reintroduction
of this bug, and moves the c::init_locale() function to the common module.