Cross-compilation from armhf to mips64el

[Andreas Enge <andreas@enge.fr>]

Hello,

currently, we get lots of failed jobs for armhf coming from cross-compilation,
such as
   http://hydra.gnu.org/job/gnu/master/mips64el-linux-gnu.grep-2.21.armhf-linux

I would think that the problem comes from build-aux/hydra/guix.scm, in this
function:
    (define (from-32-to-64? target)
      ;; Return true if SYSTEM is 32-bit and TARGET is 64-bit.  This hack
      ;; prevents known-to-fail cross-builds from i686-linux or armhf-linux to
      ;; mips64el-linux-gnuabi64.
      (and (or (string-prefix? "i686-" system)
               (string-prefix? "armhf-" system))
           (string-suffix? "64" target)))
since target seems to be mips64el-linux-gnu and not mips64el-linux-gnuabi64.
Then I would replace "string-suffix?" by "string-contains".

But I must have overlooked something, since hydra does not cross-build from
i686 to mips. If someone could have a look...

Andreas