use std::env; use std::ffi::OsString; use std::process; fn main() { println!("cargo:rerun-if-changed=build.rs"); println!("cargo:rustc-check-cfg=cfg(exhaustive)"); println!("cargo:rustc-check-cfg=cfg(prettyplease_debug)"); println!("cargo:rustc-check-cfg=cfg(prettyplease_debug_indent)"); let pkg_version = cargo_env_var("CARGO_PKG_VERSION"); println!("cargo:VERSION={}", pkg_version.to_str().unwrap()); } fn cargo_env_var(key: &str) -> OsString { env::var_os(key).unwrap_or_else(|| { eprintln!("Environment variable ${key} is not set during execution of build script"); process::exit(1); }) }