everything downloaded, then tarballed, then built,
now crossgcc is downloaded by coreboot.
now extract, copy crossgcc tarballs, re-compress.
TODO: simply add files to the archive, without re-
compressing the whole thing.
this is still more efficient than the old way: build
everything, then clean and compress, making another
build test on the release archive necessary; with this,
there is still only one build test per release.
with this, and the previous revisions dealing with
submodules, the source archives should now be complete.
Signed-off-by: Leah Rowe <leah@libreboot.org>