- Install lua and luarocks from the OS package repository instead of
manually downloading them. Also the luarock fork looked
unmaintained.
- Remove luarocks from the image after installing lua packages because
it's not needed after that
- Remove build-time dependencies
- Remove cached NPM packages
- Remove cached PyPi packages
- Remove dependency descriptors. These still count against the total space,
although it's a few KBs
- Install rust-clippy and rust-fmt using the OS package manager instead of
maintaining our own installation script
- Add tests for build time dependencies that are not supposed to be installed
