use rustc_version::{version, version_meta, Channel}; fn main() { // Assert we haven't travelled back in time assert!(version().unwrap().major >= 1); // Set cfg flags depending on release channel match version_meta().unwrap().channel { Channel::Stable => { println!("cargo:rustc-cfg=RUSTC_IS_STABLE"); } Channel::Beta => { println!("cargo:rustc-cfg=RUSTC_IS_BETA"); } Channel::Nightly => { println!("cargo:rustc-cfg=RUSTC_IS_NIGTHLY"); } Channel::Dev => { println!("cargo:rustc-cfg=RUSTC_IS_DEV"); } } }