fn print_elf_paths_cargo_directives(target_elf_paths: &[(String, Utf8PathBuf)]) {
    for (target_name, elf_path) in target_elf_paths.iter() {
        println!("cargo:rustc-env=SP1_ELF_{}={}", target_name, elf_path);
    }
}
Prints cargo directives setting relevant `SP1_ELF_` environment variables.
crates/build/src/build.rs