* gnu/packages/patches/gmp-arm-asm-nothumb.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/multiprecision.scm (gmp): Add patch. Include --build triplet
in configure args when building natively.
* gnu/packages/commencement.scm (gcc-final): Use bootstrap guile to
build gmp-source.