fnmain(){emit_workspace_root();}/// Emits `CURSUS_WORKSPACE_ROOT` so integration tests can locate `flake.nix`.
////// Walks up from `CARGO_MANIFEST_DIR` until it finds a directory containing
/// `flake.nix`, then sets the env var for compile-time access via `env!()`.
fnemit_workspace_root(){let manifest_dir =matchstd::env::var("CARGO_MANIFEST_DIR"){Ok(d)=> d,Err(_)=>return,};letmut dir =std::path::PathBuf::from(&manifest_dir);loop{if dir.join("flake.nix").exists(){println!("cargo:rustc-env=CURSUS_WORKSPACE_ROOT={}", dir.display());return;}if!dir.pop(){eprintln!("cargo:warning=Could not find flake.nix above {manifest_dir}");break;}}}