rust/cffi build

build.rs

extern crate cc;
use std::path::Path;

fn main() {
    let host_target = "x86_64-apple-darwin";
    cc::Build::new()
        .cpp(true)
        .file("src/cpp/hello.cpp")
        .include("src/cpp")
        .out_dir(Path::new("."))
        .target(host_target)
        .host(host_target)
        .opt_level(0)
        .compile("libcrust.a");
}