Merge rust-bitcoin#71: Fix to download the correct binary for Apple silicon Macs

d692352 fix: codesign the bitcoin binary on mac arm64 (Cliff Syner)
f38db55 fix: use arm64 binary for apple silicon (Cliff Syner)

Pull request description:

  Previously, using the (node) crate with the `from_downloaded()` trait would fail on apple silicon with `bad CPU type in executable`

  Part of the update includes some code-signing, this is necessary for unsigned binaries (like bitcoind) to run on Arm Macs:
  bitcoin/bitcoin#26694 (comment)

ACKs for top commit:
  tcharding:
    utACK d692352

Tree-SHA512: 7e01009622d3c3a16ee296e068bb881a63656eb8e74f3e51249c3079f76cee59822fe28df5023fbe183d4067dd4869fcd3be346a4a664316fb8e27747cc2f6c7

Author: tcharding

node/build.rs

@@ -20,7 +20,7 @@ mod download {
 
     include!("src/versions.rs");
 
-    #[cfg(all(target_os = "macos", any(target_arch = "x86_64", target_arch = "aarch64"),))]
+    #[cfg(all(target_os = "macos", target_arch = "x86_64"))]
     fn download_filename() -> String {
         if cfg!(not(feature = "23_2")) {
             format!("bitcoin-{}-osx64.tar.gz", &VERSION)
@@ -29,6 +29,9 @@ mod download {
         }
     }
 
+    #[cfg(all(target_os = "macos", target_arch = "aarch64"))]
+    fn download_filename() -> String { format!("bitcoin-{}-arm64-apple-darwin.tar.gz", &VERSION) }
+
     #[cfg(all(target_os = "linux", target_arch = "x86_64"))]
     fn download_filename() -> String { format!("bitcoin-{}-x86_64-linux-gnu.tar.gz", &VERSION) }
 
@@ -153,6 +156,24 @@ mod download {
                     }
                 }
             }
+
+            // Code signing for arm64 macOS:
+            #[cfg(all(target_os = "macos", target_arch = "aarch64"))]
+            {
+                use std::process::Command;
+                let status = Command::new("codesign")
+                    .arg("-s")
+                    .arg("-")
+                    .arg(existing_filename.to_str().unwrap())
+                    .status()
+                    .with_context(|| "failed to execute codesign")?;
+                if !status.success() {
+                    return Err(anyhow::anyhow!(
+                        "codesign failed with exit code {}",
+                        status.code().unwrap_or(-1)
+                    ));
+                }
+            }
         }
         Ok(())
     }