auto_enums_derive 0.2.0

This library provides an attribute macro like a wrapper of `#[derive]`, implementing the supported traits and passing unsupported traits to `#[derive]`.
Documentation 
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use std::env;
use std::process::Command;
use std::str;

fn main() {
    println!("cargo:rerun-if-changed=build.rs");

    let minor = match rustc_minor_version() {
        Some(x) => x,
        None => return,
    };

    if minor >= 33 {
        println!("cargo:rustc-cfg=stable_1_33");
    }
}

fn rustc_minor_version() -> Option<u32> {
    env::var_os("RUSTC")
        .and_then(|rustc| Command::new(rustc).arg("--version").output().ok())
        .and_then(|output| {
            str::from_utf8(&output.stdout).ok().and_then(|version| {
                let mut pieces = version.split('.');
                if pieces.next() != Some("rustc 1") {
                    return None;
                }
                pieces.next()?.parse().ok()
            })
        })
}