wasi-nn: rebuild if the witx files change

Cargo.lock

@@ -2727,6 +2727,7 @@ dependencies = [
  "log",
  "openvino",
  "thiserror",
+ "walkdir",
  "wasmtime",
  "wasmtime-runtime",
  "wasmtime-wasi",

crates/wasi-nn/Cargo.toml

@@ -25,5 +25,8 @@ wiggle = { path = "../wiggle", version = "0.21.0" }
 openvino = "0.1.5"
 thiserror = "1.0"
 
+[build-dependencies]
+walkdir = "2.3"
+
 [badges]
 maintenance = { status = "experimental" }

crates/wasi-nn/build.rs

@@ -7,4 +7,9 @@ fn main() {
     // This is necessary for Wiggle/Witx macros.
     let wasi_root = PathBuf::from("./spec").canonicalize().unwrap();
     println!("cargo:rustc-env=WASI_ROOT={}", wasi_root.display());
+
+    // Also automatically rebuild if the Witx files change
+    for entry in walkdir::WalkDir::new(wasi_root) {
+        println!("cargo:rerun-if-changed={}", entry.unwrap().path().display());
+    }
 }