use rustc_version::{version_meta, Channel}; fn main() { if let Channel::Nightly = version_meta().unwrap().channel { println!("cargo:rustc-cfg=nightly") } // Configure track_caller based on Rust version if let Ok(version) = rustc_version::version() { if version >= rustc_version::Version::new(1, 46, 0) { println!("cargo:rustc-cfg=track_caller"); } } // Add check-cfg for conditional configurations println!("cargo:rustc-check-cfg=cfg(doc_cfg)"); println!("cargo:rustc-check-cfg=cfg(track_caller)"); println!("cargo:rustc-check-cfg=cfg(nightly)"); }