build.rs

extern crate bindgen;

use std::env;
use std::path::PathBuf;

fn main() {
    let bindings = bindgen::Builder::default()
        // I just imported it straight from where it was on my computer.
        // If we were building a real module we might not want to do this!
        // Also if you're trying this on macOS this header file may not be
        // in this particular location
        .header("emacs-module.h")
        // We want to specify our own emacs_module_init function, so we won't
        // generate one in Rust automatically
        .blocklist_function("emacs_module_init")
        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
        // Generate the bindings
        .generate()
        // Explode if something goes wrong
        .expect("Unable to generate bindings");

    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
    bindings
        .write_to_file(out_path.join("bindings.rs"))
        .expect("Couldn't write bindings!");
}