num-traits/build.rs

36 lines
929 B
Rust

use std::env;
use std::io::Write;
use std::process::{Command, Stdio};
fn main() {
if probe("fn main() { 0i128; }") {
println!("cargo:rustc-cfg=has_i128");
} else if env::var_os("CARGO_FEATURE_I128").is_some() {
panic!("i128 support was not detected!");
}
}
/// Test if a code snippet can be compiled
fn probe(code: &str) -> bool {
let rustc = env::var_os("RUSTC").unwrap_or_else(|| "rustc".into());
let out_dir = env::var_os("OUT_DIR").expect("environment variable OUT_DIR");
let mut child = Command::new(rustc)
.arg("--out-dir")
.arg(out_dir)
.arg("--emit=obj")
.arg("-")
.stdin(Stdio::piped())
.spawn()
.expect("rustc probe");
child
.stdin
.as_mut()
.expect("rustc stdin")
.write_all(code.as_bytes())
.expect("write rustc stdin");
child.wait().expect("rustc probe").success()
}