gnu: bc: Don't duplicate bootstrap phase.

* gnu/packages/algebra.scm (bc)[arguments]: Use custom 'autoconf phase
to replace standard 'bootstrap phase.

gnu/packages/algebra.scm

@@ -4,7 +4,7 @@
 ;;; Copyright © 2016, 2017, 2018, 2019, 2020, 2021 Nicolas Goaziou <mail@nicolasgoaziou.fr>
 ;;; Copyright © 2014, 2018 Mark H Weaver <mhw@netris.org>
 ;;; Copyright © 2016, 2018, 2019 Ricardo Wurmus <rekado@elephly.net>
-;;; Copyright © 2017, 2020 Efraim Flashner <efraim@flashner.co.il>
+;;; Copyright © 2017, 2020, 2021 Efraim Flashner <efraim@flashner.co.il>
 ;;; Copyright © 2017–2021 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2017 Marius Bakke <mbakke@fastmail.com>
 ;;; Copyright © 2017, 2019 Eric Bavier <bavier@member.fsf.org>
@@ -711,7 +711,7 @@ binary.")
        (list "--with-readline")
        #:phases
        (modify-phases %standard-phases
-         (add-after 'unpack 'autogen
+         (replace 'bootstrap
            (lambda _
              (invoke "autoreconf" "-vif"))))))
     (home-page "https://www.gnu.org/software/bc/")