Move the check-cfg lint stuff from the build scritp to Cargo.toml

Cargo.toml

@@ -87,6 +87,17 @@ trybuild = "1.0"
 [target.'cfg(rustver)'.build-dependencies]
 rustc_version = "0.4.0"
 
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = [
+    "cfg(armv5te)",
+    "cfg(beta_clippy)",
+    "cfg(kani)",
+    "cfg(mips)",
+    "cfg(rustver)",
+    "cfg(skip_large_mem_tests)",
+    "cfg(trybuild)",
+] }
+
 # https://docs.rs/about/metadata
 [package.metadata.docs.rs]
 # Build the doc at docs.rs with some features enabled.

build.rs

@@ -1,15 +1,3 @@
-#![allow(unexpected_cfgs)] // for `#[cfg(rustver)]` in this build.rs.
-
-const ALLOWED_CFG_NAMES: &[&str] = &[
-    "armv5te",
-    "beta_clippy",
-    "kani",
-    "mips",
-    "rustver",
-    "skip_large_mem_tests",
-    "trybuild",
-];
-
 #[cfg(rustver)]
 fn main() {
     use rustc_version::version;
@@ -18,18 +6,7 @@ fn main() {
         "cargo:rustc-env=RUSTC_SEMVER={}.{}",
         version.major, version.minor
     );
-
-    allow_cfgs(ALLOWED_CFG_NAMES);
 }
 
 #[cfg(not(rustver))]
-fn main() {
-    allow_cfgs(ALLOWED_CFG_NAMES);
-}
-
-/// Tells `rustc` to allow `#[cfg(...)]` with the given names.
-fn allow_cfgs(names: &[&str]) {
-    for name in names.iter() {
-        println!("cargo:rustc-check-cfg=cfg({name})");
-    }
-}
+fn main() {}