| use std::env; |
| use std::process::Command; |
| use std::str; |
| |
| fn main() { |
| /* |
| * If `core::ffi::c_void` exists, libc can just re-export it. Otherwise, it |
| * must define an incompatible type to retain backwards-compatibility. |
| */ |
| if rustc_minor_version().expect("Failed to get rustc version") >= 30 { |
| println!("cargo:rustc-cfg=core_cvoid"); |
| } |
| } |
| |
| fn rustc_minor_version() -> Option<u32> { |
| macro_rules! otry { |
| ($e:expr) => { |
| match $e { |
| Some(e) => e, |
| None => return None, |
| } |
| }; |
| } |
| |
| let rustc = otry!(env::var_os("RUSTC")); |
| let output = otry!(Command::new(rustc).arg("--version").output().ok()); |
| let version = otry!(str::from_utf8(&output.stdout).ok()); |
| let mut pieces = version.split('.'); |
| |
| if pieces.next() != Some("rustc 1") { |
| return None; |
| } |
| |
| otry!(pieces.next()).parse().ok() |
| } |