fn main() {
#[cfg(not(any(feature = "backend-gnupg-bin", feature = "backend-gpgme")))]
{
compile_error!("no crypto backend selected, must set any of these features: backend-gnupg-bin, backend-gpgme");
}
#[cfg(any(feature = "backend-gpgme", feature = "backend-gnupg-bin"))]
println!("cargo:rustc-cfg=feature=\"_crypto-gpg\"");
}