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|
use std::env::{self, VarError};
use std::fs;
use std::path::Path;
use std::process;
const TEMPLATE: &str = "\
/// Produces the value of TARGET as a string literal.
#[macro_export]
macro_rules! target {
() => {
\"{TARGET}\"
};
}
/// Produces the value of HOST as a string literal.
#[macro_export]
macro_rules! host {
() => {
\"{HOST}\"
};
}
";
fn main() {
println!("cargo:rerun-if-changed=build.rs");
println!("cargo:rustc-check-cfg=cfg(host_os, values(\"windows\"))");
let target = env_var("TARGET");
let host = env_var("HOST");
let out_dir = env_var("OUT_DIR");
let out = Path::new(&out_dir).join("macros.rs");
let macros = TEMPLATE
.replace("{TARGET}", &target.escape_debug().to_string())
.replace("{HOST}", &host.escape_debug().to_string());
fs::write(out, macros).unwrap();
if let Some("windows") = host.split('-').nth(2) {
println!("cargo:rustc-cfg=host_os=\"windows\"");
}
}
fn env_var(key: &str) -> String {
match env::var(key) {
Ok(value) => value,
Err(VarError::NotPresent) => {
eprintln!("Environment variable ${key} is not set during execution of build script");
process::exit(1);
}
Err(VarError::NotUnicode(_)) => {
eprintln!("Environment variable ${key} is non-UTF8 during execution of build script");
process::exit(1);
}
}
}
|
