perl: Disable setlocale usage under musl

perl: Disable setlocale usage under musl

While setlocale() is present, musl currently doesn't provide a suitable implementation.
It'll silently accept every locale, even if not present at all, defaulting them
to C.UTF-8. This will confuse applications as well as our testsuite(see lib/locale.t).

Even if a locale does exist, it's effects will not apply to an extent that will
satisfy many applications.

Avoid further mischief here and just disable setlocale() for now.

Signed-off-by: Marcel Denia <redacted>