use std::env; fn main() { println!("cargo:rustc-check-cfg=cfg(ossl110)"); if let Ok(v) = env::var("DEP_OPENSSL_VERSION_NUMBER") { let version = u64::from_str_radix(&v, 16).unwrap(); if version >= 0x1010_0000 { println!("cargo:rustc-cfg=ossl110"); } } }