Sergei Trofimovich authored Jul 11, 2020 and Marge Bot committed Jul 14, 2020

Recently build system migrated from INTEGER_LIBRARY to BIGNUM_BACKEND.
But gitlab CI was never updated. Let's enable BIGNUM_BACKEND=native.

Bug: ghc/ghc#18437


Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>