paths/paths.rs
extern crate autocfg;
fn main() {
// Normally, cargo will set `OUT_DIR` for build scripts.
let ac = autocfg::AutoCfg::with_dir("target").unwrap();
// since ancient times...
ac.emit_has_path("std::vec::Vec");
ac.emit_path_cfg("std::vec::Vec", "has_vec");
// rustc 1.10.0
ac.emit_has_path("std::panic::PanicInfo");
ac.emit_path_cfg("std::panic::PanicInfo", "has_panic_info");
// rustc 1.20.0
ac.emit_has_path("std::mem::ManuallyDrop");
ac.emit_path_cfg("std::mem::ManuallyDrop", "has_manually_drop");
// rustc 1.25.0
ac.emit_has_path("std::ptr::NonNull");
ac.emit_path_cfg("std::ptr::NonNull", "has_non_null");
}