use std::env;
fn main() {
println!("cargo:rerun-if-changed=build.rs");
let target = env::var("TARGET").unwrap();
maybe_enable_use_proc_macro(&target);
}
fn maybe_enable_use_proc_macro(target: &str) {
// wasm targets don't have the `proc_macro` crate, disable this feature.
if target.contains("wasm32") {
return
}
// There are currently no musl builds of the compiler, so proc_macro is
// always missing, so disable this feature.
if target.contains("-musl") {
return
}
// Otherwise, only enable it if our feature is actually enabled.
if cfg!(feature = "proc-macro") {
println!("cargo:rustc-cfg=use_proc_macro");
}
}