1extern crate autocfg;
2
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_trait("std::ops::Add");
9    ac.emit_trait_cfg("std::ops::Add", "has_ops");
10
11    // trait parameters have to be provided
12    ac.emit_has_trait("std::borrow::Borrow<str>");
13    ac.emit_trait_cfg("std::borrow::Borrow<str>", "has_borrow");
14
15    // rustc 1.8.0
16    ac.emit_has_trait("std::ops::AddAssign");
17    ac.emit_trait_cfg("std::ops::AddAssign", "has_assign_ops");
18
19    // rustc 1.12.0
20    ac.emit_has_trait("std::iter::Sum");
21    ac.emit_trait_cfg("std::iter::Sum", "has_sum");
22
23    // rustc 1.28.0
24    ac.emit_has_trait("std::alloc::GlobalAlloc");
25    ac.emit_trait_cfg("std::alloc::GlobalAlloc", "has_global_alloc");
26}
27