We drop our MIPS target because it no longer works.[1] We were
previously using it as a means of testing ripgrep in a big endian
environment. So to achieve that without MIPS, we test on powerpc64 and
s390x. (No particular reason to do both, but why not.)
We also add aarch64 as a proxy for at least ensuring everything works
for the same architecture as Apple silicon. It's not a guarantee that
everything works, but it seems better than nothing until we can actually
test Apple silicon in CI.
[1]: c788378d6f
Looks like the old japaric images are bunk. We update our docker image
to be based on the new rustembedded images and configure cross to use
it.
Turns out that this wasn't due to a stale docker image, but rather, a
bug in cross: https://github.com/rust-embedded/cross/issues/357
We work around that bug by installing the master branch of cross. Sigh.
The docker image that the Linux binary is now built in does not have
ASCII doc installed, so setup Cross to point to my own image with those
tools installed.
