refactor: add support for rustc-check-cfg

.github/workflows/lint.yaml

@@ -90,7 +90,7 @@ jobs:
       - name: Install Cargo Udeps
         uses: taiki-e/install-action@v2
         with:
-          tool: cargo-udeps
+          tool: cargo-udeps@0.1.48
 
       - name: Run Cargo Udeps
         run: cargo +nightly udeps --locked --all-targets

crates/wdk-build/build.rs

@@ -3,10 +3,16 @@
 
 //! Build script for the `wdk-build` crate.
 
-#[rustversion::nightly]
 fn main() {
-    println!("cargo:rustc-cfg=nightly_toolchain");
+    println!("cargo::rustc-check-cfg=cfg(nightly_toolchain)");
+    setup_nightly_cfgs();
+}
+
+// Custom attributes cannot be applied to expressions yet, so separate functions are required for nightly/non-nightly: https://github.com/rust-lang/rust/issues/15701
+#[rustversion::nightly]
+fn setup_nightly_cfgs() {
+    println!("cargo::rustc-cfg=nightly_toolchain");
 }
 
 #[rustversion::not(nightly)]
-fn main() {}
+const fn setup_nightly_cfgs() {}

crates/wdk-build/src/lib.rs

@@ -620,7 +620,7 @@ impl Config {
             return Err(ExportError::MissingLinksValue(var_error));
         }
         println!(
-            "cargo::{}={}",
+            "cargo::metadata={}={}",
             Self::CARGO_CONFIG_KEY,
             serde_json::to_string(self)?
         );