| use std::process::Command; | |
| fn main() { | |
| if let Ok(v) = Command::new("rustc").arg("--version").output() { | |
| let s = match String::from_utf8(v.stdout) { | |
| Ok(s) => s, | |
| _ => return, | |
| }; | |
| if !s.starts_with("rustc ") { | |
| return; | |
| } | |
| if let Some(s) = s.split(' ').skip(1).next() { | |
| let s = s.split('.').collect::<Vec<_>>(); | |
| if s.len() < 3 { | |
| return; | |
| } | |
| if s[0] == "1" && u32::from_str_radix(&s[1], 10) | |
| .map(|nb| nb < 30) | |
| .unwrap_or_else(|_| false) { | |
| println!("cargo:rustc-cfg=feature=\"old_macros\""); | |
| } | |
| } | |
| } | |
| } |