1@README.md
2
3- Rust builds at `-Copt-level=3` for every target; the reason is in the
4  comment in `BUCK`. It is a property of the project, not a release mode.
5- Builds outside `nix develop` pick up whatever rustc the host has, or none.
6  Always build through the devshell.
7- buck2's system cxx toolchain looks up plain `clang`/`clang++` and links
8  with `-fuse-ld=lld`; both come from the devshell (`../flake.nix` says
9  why). Without them every Rust binary and build script fails at the link.