rustc/vendor/native-tls/build.rs

use std::env;

fn main() {
    if let Ok(version) = env::var("DEP_OPENSSL_VERSION_NUMBER") {
        let version = u64::from_str_radix(&version, 16).unwrap();

        if version >= 0x1_01_00_00_0 {
            println!("cargo:rustc-cfg=have_min_max_version");
        }
    }

    if let Ok(version) = env::var("DEP_OPENSSL_LIBRESSL_VERSION_NUMBER") {
        let version = u64::from_str_radix(&version, 16).unwrap();

        if version >= 0x2_06_01_00_0 {
            println!("cargo:rustc-cfg=have_min_max_version");
        }
    }
}