PURPOSE
Possible issue causing segfaults on threaded Perl 5.18.x.
AUTHOR
Graham Knop <haarg@cpan.org>.
COPYRIGHT AND LICENCE
This software is copyright (c) 2014, 2017-2020 by Graham Knop.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.