Fix wen_restart proto compilation: (#33596)

* Fix wen_restart proto compilation:
- should recompile when proto changes
- no need for customization

* There is only one proto file, no need for loop.

wen-restart/build.rs

@@ -1,9 +1,6 @@
 extern crate rustc_version;
 
-use {
-    rustc_version::{version_meta, Channel},
-    std::io::Result,
-};
+use std::io::Result;
 
 fn main() -> Result<()> {
     const PROTOC_ENVAR: &str = "PROTOC";
@@ -12,30 +9,11 @@ fn main() -> Result<()> {
         std::env::set_var(PROTOC_ENVAR, protobuf_src::protoc());
     }
 
-    // Copied and adapted from
-    // https://github.com/Kimundi/rustc-version-rs/blob/1d692a965f4e48a8cb72e82cda953107c0d22f47/README.md#example
-    // Licensed under Apache-2.0 + MIT
-    match version_meta().unwrap().channel {
-        Channel::Stable => {
-            println!("cargo:rustc-cfg=RUSTC_WITHOUT_SPECIALIZATION");
-        }
-        Channel::Beta => {
-            println!("cargo:rustc-cfg=RUSTC_WITHOUT_SPECIALIZATION");
-        }
-        Channel::Nightly => {
-            println!("cargo:rustc-cfg=RUSTC_WITH_SPECIALIZATION");
-        }
-        Channel::Dev => {
-            println!("cargo:rustc-cfg=RUSTC_WITH_SPECIALIZATION");
-            // See https://github.com/solana-labs/solana/issues/11055
-            // We may be running the custom `rust-bpf-builder` toolchain,
-            // which currently needs `#![feature(proc_macro_hygiene)]` to
-            // be applied.
-            println!("cargo:rustc-cfg=RUSTC_NEEDS_PROC_MACRO_HYGIENE");
-        }
-    }
+    let proto_base_path = std::path::PathBuf::from("proto");
+    let proto = proto_base_path.join("wen_restart.proto");
+    println!("cargo:rerun-if-changed={}", proto.display());
 
     // Generate rust files from protos.
-    prost_build::compile_protos(&["proto/wen_restart.proto"], &["proto/"])?;
+    prost_build::compile_protos(&[proto], &[proto_base_path])?;
     Ok(())
 }