[pstricks] pstricks-add fails basic test after system upgrade

[Brandon Kuczenski]

Hi folks,
I recently upgraded my system (arch linux) for the first time in about 90
days. Now I cannot use the pstricks-add package.
My example is as minimal as can be:


\documentclass{article}

\usepackage{pstricks-add}

\listfiles
\begin{document}
hello world!
\end{document}

It produces the following error:

! Undefined control sequence.
<argument> \LaTeX3 error:
                           Use \cs_prefix_spec:N not
\token_get_prefix_spec:...
l.6 \begin{document}

?

The file listing is also not generated because of the error. However I can
confirm that I am using v3.89a of pstricks-add, which is the same as I see
on CTAN.

The log file is attached.

If I substitute "pstricks" for "pstricks-add", then the document loads
correctly.

Any idea what is wrong? I know nothing of LaTeX3 and google didn't help.

Thanks in advance,
Brandon
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