I realized Guix already provided "libao", as "ao" variable. However,
I don't know why it isn't "public".

I also packaged "mpfi".

Since all dependencies of "giac-xcas" are now available, I can update
the package definition.

I'm not sure about input "texlive-minimal". Debian package doesn't have
it. However, configure script checks for latex, makeindex, pdflatex and
dvips, probably so as to build documentation. OTOH, I don't think
default make dance builds documentation: it probably copies it directly
from the tarball, so it may be useless to provide the input. As a last
point, xcas itself provides a feature to print formulas as LaTeX. So,
all in all, texlive-minimal may be a propagated-input, AFAIU.

WDYT?

In any case, here are the patches. Thank you for reading so far.

Regards,