fn main() {
let date = std::process::Command::new("date")
.args(["-u", "+%Y%m%d"])
.output()
.ok()
.filter(|o| o.status.success())
.and_then(|o| String::from_utf8(o.stdout).ok())
.map(|s| s.trim().to_string())
.unwrap_or_else(|| "unknown".to_string());
println!("cargo:rustc-env=BUILD_DATE={date}");
}