bug#33754: guix-0.16.0-4.60b0402 fails to build on armhf-linux

[Mark H Weaver]

guix-0.16.0-4.60b0402 fails to build on armhf-linux, in what appears to
be a reproducible failure.

  https://hydra.gnu.org/build/3281991

Two tests fail: tests/graph.scm and tests/guix-package.sh.  Both
failures are ultimately caused by the following error:

  (match-error "match" "no matching pattern" "armhf-linux")

It's possible that this problem is partly fixed by commit 966629a,

  
https://git.savannah.gnu.org/cgit/guix.git/commit/?id=966629a114fd90153784dfdbe5e332e0ac94f1bc

but I think that we also need to update our 'guix' package so that
armhf-linux systems will be usable again.

       Mark