Fixes a regression introduced in dea91108cf6b9bb46071c8f65c9abf834c5b064d. * build-aux/hydra/gnu-system.scm (hydra-jobs)[cross-jobs](either): Add third parameter and honor it.
Fixes a regression introduced in dea91108cf6b9bb46071c8f65c9abf834c5b064d. * build-aux/hydra/gnu-system.scm (hydra-jobs)[cross-jobs](either): Add third parameter and honor it.