walking the zip prevents minizip from re-reading the same
data repeatedly from the actual backing filesystem.
also improves most usages of minizip to allow for >4GB,
files altho we probably don't need it
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
