Segmentation fault when using encoding ':locale' and creating a new thre

Florent Bayle wrote:
> The following code segfault on my system
> perl -Mthreads -e "use encoding ':locale';
threads->create(sub {});"

Bo Lindbergh wrote:
> Yet another symptom of PerlIO::encoding not being
thread safe.
> See <http://rt.perl.org/rt3/Public/Bug/Display.html?id=319
23> for
> the full story.

Gee, shouldn't this be documented in the POD.  Patch
attached.