/// Marks the crate as being compiled with unstable features enabled.
#[rustversion::nightly]fnmain(){println!("cargo::rustc-check-cfg=cfg(unstable)");println!("cargo:rustc-cfg=unstable");}/// Marks the crate as being compiled without unstable features.
#[rustversion::not(nightly)]fnmain(){println!("cargo::rustc-check-cfg=cfg(unstable)");}