bug#23961: fixed a while back

[Robert Vollmert]

commit 314b63e0b4372681aec165113ae2a0349eaaa357
Author: Danny Milosavljevic <dan...@scratchpost.org>
Date:   Wed Jul 11 11:02:51 2018 +0200

    import: hackage: Support "custom-setup" field.
    
    Fixes <https://bugs.gnu.org/23961>.
    
    * guix/import/cabal.scm (make-cabal-parser): Modify.
    (is-custom-setup): New variable.
    (lex-custom-setup): New procedure.
    (is-id): Modify.
    (lex-version): Modify.
    (<cabal-custom-setup>): New record type.
    (eval-cabal): Modify.
    (dependencies): Add parameter.