fn main() { println!("cargo:rerun-if-changed=build.rs"); maybe_enable_asm(); } #[rustversion::before(1.59.0)] fn maybe_enable_asm() { // } #[rustversion::since(1.59.0)] fn maybe_enable_asm() { // https://github.com/rust-lang/rust/pull/92816 println!("cargo:rustc-cfg=avr_device_asm_macro"); }