gnu: pynac: Remove package.

The package was integrated into the Sagemath source code in 2021.

* gnu/packages/sagemath.scm (pynac): Remove variable.

Change-Id: I5c6a90ed1747852d0dc4e73b79ce9daa34d876c7

gnu/packages/sagemath.scm

@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2019, 2024 Andreas Enge <andreas@enge.fr>
+;;; Copyright © 2019 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2019 Nicolas Goaziou <mail@nicolasgoaziou.fr>
 ;;; Copyright © 2019, 2020 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
@@ -170,33 +170,6 @@ (define-public libhomfly
     (license license:public-domain)
     (home-page "https://github.com/miguelmarco/libhomfly")))
 
-(define-public pynac
-  (package
-    (name "pynac")
-    (version "0.7.29")
-    (source
-     (origin
-       (method git-fetch)
-       (uri (git-reference
-              (url "https://github.com/pynac/pynac/")
-              (commit (string-append "pynac-" version))))
-       (file-name (git-file-name name version))
-       (sha256
-        (base32 "1h2b85rmmrsjnqk8z5d811r1lc0h64g7dyk7gfbwyapdcmx7pi51"))))
-    (build-system gnu-build-system)
-    (native-inputs
-     (list autoconf automake libtool pkg-config))
-    (inputs
-     (list flint gmp python singular))
-    (synopsis "Sage fork of GiNaC")
-    (description "Pynac is a derivative of the C++ library GiNaC, which
-allows manipulation of symbolic expressions.  It currently provides the
-backend for symbolic expressions in Sage.  The main difference between
-Pynac and GiNaC is that Pynac relies on Sage to provide the operations
-on numerical types, while GiNaC depends on CLN for this purpose.")
-    (license license:gpl2+)
-    (home-page "http://pynac.org/")))
-
 ;; Sage has become upstream of the following package.
 (define-public zn-poly
   (package