Things I had to do

[ehildenb]

Things were hard to get working. In particular, to get make smir-parse-tests working, I had to run some commands

% rustup toolchain install nightly-2024-11-29 --component llvm-tools --component rustc-dev --component rust-src
% rustup default nightly-2024-11-29-x86_64-unknown-linux-gnu

I could not find these incantations in the book of spells.

This was in particular to get this PR going: #537