Update: I've ripped my code contribution out of this node and submitted it as a separate answer.

I agree with the other posters that the best (as in portable and maintainable) solution would be to use a CPAN module.

qx{ (LANG=C ; /sbin/ifconfig -a 2>&1) }

I think it would be better to omit the ";" to make sure that the variable gets into the environment. Better yet would be to use "LC_ALL=C" because afaik that overrides all locales (including LANG).