You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: build.rs
    path of file: ./repos/flutter-rs/flutter-engine-sys
    
    the code of the file until where you have to start completion: use bindgen::EnumVariation;
use std::path::PathBuf;

fn main() {
    let target = std::env::var("TARGET").unwrap();
    let mut clang_args: Vec<String> = Vec::new();

    
    
fn main() {
    let target = std::env::var("TARGET").unwrap();
    let mut clang_args: Vec<String> = Vec::new();

    // This adds the sysroot specific to the android NDK
    if target.contains("android") {
        let ndk_home = std::env::var("NDK_HOME").expect("NDK_HOME is set");
        let sysroot = PathBuf::from(ndk_home).join("sysroot");
        clang_args.push("--sysroot".into());
        clang_args.push(sysroot.to_str().unwrap().to_string());
    }

    // This adds the sysroot specific to the apple SDK for clang.
    if let Some(sdk_path) = sdk_path(&target) {
        clang_args.push("-isysroot".into());
        clang_args.push(sdk_path);
    }

    // https://github.com/rust-lang/rust-bindgen/issues/1211
    let target = if target == "aarch64-apple-ios" {
        String::from("arm64-apple-ios")
    } else {
        target
    };
    clang_args.push(format!("--target={}", target));

    let bindings = bindgen::Builder::default()
        .header("flutter-engine.h")
        .default_enum_style(EnumVariation::Rust {
            non_exhaustive: false,
        })
        .clang_args(&clang_args)
        .generate()
        .expect("Unable to generate bindings");

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