extern crate cc;

use std::{env, fs};

fn main() {
    let _crate_dir = env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR not set");
    let target = env::var("TARGET").unwrap();

    println!("cargo:rerun-if-changed=src/c");

    // The Redoxer toolchain and some upstream nightlies keep the older
    // `VaList<'a>` ABI for `extern "C" fn(...)` parameters, while others
    // pass `VaListImpl<'f>` and require `.as_va_list()` to obtain
    // `VaList<'_, '_>`. This is a host-compiler property, so probe
    // directly with the host rustc (avoiding autocfg's target probing).
    println!("cargo:rustc-check-cfg=cfg(relibc_valist_impl)");
    let rustc = env::var("RUSTC").unwrap_or_else(|_| "rustc".to_string());
    let out_dir = env::var("OUT_DIR").unwrap_or_else(|_| "/tmp".to_string());
    let probe_file = std::path::Path::new(&out_dir).join("relibc_valist_probe.rs");
    let probe_out = std::path::Path::new(&out_dir).join("librelibc_valist_probe.rlib");
    std::fs::write(
        &probe_file,
        "#![feature(c_variadic)] pub fn _relibc_valist_probe(_: core::ffi::VaList<'_, '_>) {}",
    )
    .ok();
    let probe_ok = std::process::Command::new(&rustc)
        .args([
            "--crate-type",
            "lib",
            "--edition",
            "2024",
            probe_file.to_str().unwrap(),
            "-o",
            probe_out.to_str().unwrap(),
        ])
        .status()
        .ok()
        .map_or(false, |s| s.success());
    if probe_ok {
        println!("cargo:rustc-cfg=relibc_valist_impl");
    }

    let mut cc_builder = &mut cc::Build::new();

    cc_builder = cc_builder.flag("-nostdinc").flag("-nostdlib");

    if target.starts_with("aarch64") {
        cc_builder = cc_builder.flag("-mno-outline-atomics")
    }

    cc_builder
        .flag("-fno-stack-protector")
        .flag("-Wno-expansion-to-defined")
        .files(
            fs::read_dir("src/c")
                .expect("src/c directory missing")
                .map(|res| res.expect("read_dir error").path()),
        )
        .compile("relibc_c");

    println!("cargo:rustc-link-lib=static=relibc_c");
}