fn main() {
if is_nightly().unwrap_or(false) {
println!("cargo:rustc-cfg=nightly");
}
}
fn is_nightly() -> Option<bool> {
let rustc = std::env::var_os("RUSTC")?;
let output = std::process::Command::new(rustc)
.arg("--version")
.output()
.ok()?;
let version = core::str::from_utf8(&output.stdout).ok()?;
let nightly = version.contains("nightly") || version.contains("dev");
Some(nightly)
}