use std::env; fn main() { println!("cargo:rerun-if-changed=build.rs"); // Decide ideal limb width for arithmetic in the float parser. Refer to // src/lexical/math.rs for where this has an effect. let target_arch = env::var("CARGO_CFG_TARGET_ARCH").unwrap(); match target_arch.as_str() { "aarch64" | "mips64" | "powerpc64" | "x86_64" => { println!("cargo:rustc-cfg=limb_width_64"); } _ => { println!("cargo:rustc-cfg=limb_width_32"); } } }