vendor/crossbeam-epoch/build.rs

   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
  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     let cfg = match autocfg::AutoCfg::new() {
  34         Ok(cfg) => cfg,
  35         Err(e) => {
  36             println!(
  37                 "cargo:warning={}: unable to determine rustc version: {}",
  38                 env!("CARGO_PKG_NAME"),
  39                 e
  40             );
  41             return;
  42         }
  43     };
  44
  45     // Note that this is `no_`*, not `has_*`. This allows treating as the latest
  46     // stable rustc is used when the build script doesn't run. This is useful
  47     // for non-cargo build systems that don't run the build script.
  48     if NO_ATOMIC_CAS.contains(&&*target) {
  49         println!("cargo:rustc-cfg=crossbeam_no_atomic_cas");
  50     }
  51
  52     if !cfg.probe_rustc_version(1, 61) {
  53         println!("cargo:rustc-cfg=crossbeam_no_const_fn_trait_bound");
  54     }
  55
  56     println!("cargo:rerun-if-changed=no_atomic.rs");
  57 }