use cargo_metadata::MetadataCommand;
use rustc_version::{version_meta, Channel};
fn main() {
match version_meta().unwrap().channel {
Channel::Nightly => {
let metadata = MetadataCommand::new().exec().unwrap();
let package = metadata.root_package().unwrap();
for subfeature in package.features["nightly"].iter() {
println!("cargo:rustc-cfg=feature=\"{subfeature}\"");
}
}
_ => {}
}
}