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use std::env;
use std::process::Command;
use std::str;
fn main() {
println!("cargo:rerun-if-changed=build.rs");
let compiler = match rustc_minor_version() {
Some(compiler) => compiler,
None => return,
};
if compiler < 45 {
println!("cargo:rustc-cfg=no_span_mixed_site");
}
if compiler < 47 {
println!("cargo:rustc-cfg=self_span_hack");
}
}
fn rustc_minor_version() -> Option<u32> {
let rustc = env::var_os("RUSTC")?;
let output = Command::new(rustc).arg("--version").output().ok()?;
let version = str::from_utf8(&output.stdout).ok()?;
let mut pieces = version.split('.');
if pieces.next() != Some("rustc 1") {
return None;
}
pieces.next()?.parse().ok()
}