> From: Nicolas Goaziou <mail@nicolasgoaziou.fr>
> Date: Thu, 7 Apr 2016 14:43:15 +0200
> Subject: [PATCH 2/2] gnu: Add giac-xcas
>
> * gnu/packages/algebra.scm (giac-xcas): New variable.
> ---
>  gnu/packages/algebra.scm | 65 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 65 insertions(+)
>
> diff --git a/gnu/packages/algebra.scm b/gnu/packages/algebra.scm
> index abac961..74b3f71 100644
> --- a/gnu/packages/algebra.scm
> +++ b/gnu/packages/algebra.scm
[...]
> +              (sha256
> +               (base32
> +                "0cagh9nnaz7ks299b2bs3lrdclv4xbyis24zc8vf3i25p470bxsf"))
> +              ;; Disable failing test. Actually, the results are correct but
> +              ;; a sorting discrepancy prevents the test from being validated.
> +              (modules '((guix build utils)))
> +              (snippet
> +               '(substitute* "check/Makefile.in"
> +                  (("chk_fhan16") "")))))

Is there a particular reason for not patching this within the
‘arguments’ field?  Otherwise everything looks good to me.

Here is an updated patch with the suggested change and minor formatting
fixes.