use std::env; use std::fs::File; use std::io::Write; use std::path::Path; fn generate_build_vars(output_path: &Path) { let profile = env::var("PROFILE").unwrap(); let mut f = File::create(&output_path.join("build_vars.rs")).expect("Could not create user build_vars.rs file"); f.write_all(format!("static PROFILE: &str = \"{}\";", profile).as_bytes()) .expect("Unable to write user agent"); } fn main() { let out_dir = env::var_os("OUT_DIR").expect("OUT_DIR not specified"); let out_path = Path::new(&out_dir); generate_build_vars(out_path); }