contrib/fuzzystrmatch/dmetaphone.c license

contrib/fuzzystrmatch/dmetaphone.c says this:

> /***************************** COPYRIGHT NOTICES ***********************
>
> Most of this code is directly from the Text::DoubleMetaphone perl module
> version 0.05 available from http://www.cpan.org.
> It bears this copyright notice:
>
>
> Copyright 2000, Maurice Aubrey <maurice(at)hevanet(dot)com>.
> All rights reserved.
>
> This code is based heavily on the C++ implementation by
> Lawrence Philips and incorporates several bug fixes courtesy
> of Kevin Atkinson <kevina(at)users(dot)sourceforge(dot)net>.
>
> This module is free software; you may redistribute it and/or
> modify it under the same terms as Perl itself.

Is that OK? Perl is dual-licensed under the GPL and the "Artistic
License", so the question is whether the Artistic License is compatible
with the PostgreSQL license. IANAL, but I couldn't immediately figure
out what the Artistic License requires, when you pick a piece of code
and modify and embed it in another project.

- Heikki