Fixes a 'binutils-cross-boot0' build failure on mips64el.
Reported at
<https://lists.gnu.org/archive/html/guix-devel/2016-09/msg01083.html>.
* gnu/packages/patches/binutils-mips-bash-bug.patch: New file.
* gnu/packages/base.scm (binutils)[source]: Use it.
* gnu/local.mk (dist_patch_DATA): Add it.
Ludovic Courtès