1 extern crate autocfg; 2 main()3fn main() { 4 // Normally, cargo will set `OUT_DIR` for build scripts. 5 let ac = autocfg::AutoCfg::with_dir("target").unwrap(); 6 7 // since ancient times... 8 ac.emit_has_path("std::vec::Vec"); 9 ac.emit_path_cfg("std::vec::Vec", "has_vec"); 10 11 // rustc 1.10.0 12 ac.emit_has_path("std::panic::PanicInfo"); 13 ac.emit_path_cfg("std::panic::PanicInfo", "has_panic_info"); 14 15 // rustc 1.20.0 16 ac.emit_has_path("std::mem::ManuallyDrop"); 17 ac.emit_path_cfg("std::mem::ManuallyDrop", "has_manually_drop"); 18 19 // rustc 1.25.0 20 ac.emit_has_path("std::ptr::NonNull"); 21 ac.emit_path_cfg("std::ptr::NonNull", "has_non_null"); 22 } 23