1 // The rustc-cfg listed below are considered public API, but it is *unstable*
2 // and outside of the normal semver guarantees:
3 //
4 // - `crossbeam_no_atomic_cas`
5 // Assume the target does *not* support atomic CAS operations.
6 // This is usually detected automatically by the build script, but you may
7 // need to enable it manually when building for custom targets or using
8 // non-cargo build systems that don't run the build script.
9 //
10 // With the exceptions mentioned above, the rustc-cfg emitted by the build
11 // script are *not* public API.
12
13 #![warn(rust_2018_idioms)]
14
15 use std::env;
16
17 include!("no_atomic.rs");
18 include!("build-common.rs");
19
main()20 fn main() {
21 let target = match env::var("TARGET") {
22 Ok(target) => convert_custom_linux_target(target),
23 Err(e) => {
24 println!(
25 "cargo:warning={}: unable to get TARGET environment variable: {}",
26 env!("CARGO_PKG_NAME"),
27 e
28 );
29 return;
30 }
31 };
32
33 // Note that this is `no_`*, not `has_*`. This allows treating as the latest
34 // stable rustc is used when the build script doesn't run. This is useful
35 // for non-cargo build systems that don't run the build script.
36 if NO_ATOMIC_CAS.contains(&&*target) {
37 println!("cargo:rustc-cfg=crossbeam_no_atomic_cas");
38 }
39
40 println!("cargo:rerun-if-changed=no_atomic.rs");
41 }
42