| 123456789101112131415161718192021222324252627282930 | fn main() {    // Check that at least one database feature is enabled    let has_database = cfg!(feature = "sqlite") || cfg!(feature = "postgres");    if !has_database {        panic!(            "cdk-mintd requires at least one database backend to be enabled.\n\             Available database features: sqlite, postgres\n\             Example: cargo build --features sqlite"        );    }    // Check that at least one Lightning backend is enabled    let has_lightning_backend = cfg!(feature = "cln")        || cfg!(feature = "lnd")        || cfg!(feature = "lnbits")        || cfg!(feature = "fakewallet")        || cfg!(feature = "grpc-processor")        || cfg!(feature = "ldk-node");    if !has_lightning_backend {        panic!(            "cdk-mintd requires at least one Lightning backend to be enabled.\n\             Available Lightning backends: cln, lnd, lnbits, fakewallet, grpc-processor\n\             Example: cargo build --features \"sqlite fakewallet\""        );    }    println!("cargo:rerun-if-changed=build.rs");}
 |