diff --git a/.github/workflows/native_build.yml b/.github/workflows/native_build.yml
index 102fa1b6..af4bdd2a 100644
--- a/.github/workflows/native_build.yml
+++ b/.github/workflows/native_build.yml
@@ -27,9 +27,10 @@ jobs:
           curl -o C:/cacert.pem https://curl.se/ca/cacert.pem
           echo "SSL_CERT_FILE=C:/cacert.pem" | Out-File -FilePath $env:GITHUB_ENV -Append
         if: runner.os == 'Windows'
-      - run: |
-          sudo xcode-select -s /Applications/Xcode_15.0.app
+      - uses: SwiftyLab/setup-swift@latest
         if: runner.os == 'macOS'
+        with:
+          swift-version: '5.9'
       - name: Test Full RFC Compliance
         run: cargo test --all-features --verbose --workspace
       - name: Test Bare Bones
diff --git a/mls-rs-crypto-cryptokit/build.rs b/mls-rs-crypto-cryptokit/build.rs
index e416be9e..94e91fac 100644
--- a/mls-rs-crypto-cryptokit/build.rs
+++ b/mls-rs-crypto-cryptokit/build.rs
@@ -1,83 +1,83 @@
-#![cfg(any(target_os = "macos", target_os = "ios"))]
+// This script should not run on any platform besides macOS, but making the whole file conditional
+// results in `cargo` complaining about there being no `main()` method in build.rs.
+#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+fn main() {}
 
+#[cfg(any(target_os = "macos", target_os = "ios"))]
 fn main() {
-    link_swift();
-    link_swift_package("cryptokit-bridge", "./cryptokit-bridge/");
+    swift::configure();
+    swift::link_package("cryptokit-bridge", "./cryptokit-bridge/");
 }
 
-// Copied from https://github.com/Brendonovich/swift-rs
-// With get_swift_target_info changed to print the current target
-// rather than always trying for the macosx target.
+#[cfg(any(target_os = "macos", target_os = "ios"))]
+mod swift {
+    use serde::Deserialize;
+    use std::{env, process::Command};
 
-use std::{env, process::Command};
+    #[derive(Debug, Deserialize)]
+    struct SwiftTargetInfo {
+        #[serde(rename = "unversionedTriple")]
+        pub unversioned_triple: String,
+        #[serde(rename = "librariesRequireRPath")]
+        pub libraries_require_rpath: bool,
+    }
 
-use serde::Deserialize;
+    #[derive(Debug, Deserialize)]
+    struct SwiftPaths {
+        #[serde(rename = "runtimeLibraryPaths")]
+        pub runtime_library_paths: Vec<String>,
+    }
 
-#[derive(Debug, Deserialize)]
-#[serde(rename_all = "camelCase")]
-pub struct SwiftTargetInfo {
-    pub unversioned_triple: String,
-    #[serde(rename = "librariesRequireRPath")]
-    pub libraries_require_rpath: bool,
-}
+    #[derive(Debug, Deserialize)]
+    struct SwiftTarget {
+        pub target: SwiftTargetInfo,
+        pub paths: SwiftPaths,
+    }
 
-#[derive(Debug, Deserialize)]
-#[serde(rename_all = "camelCase")]
-pub struct SwiftPaths {
-    pub runtime_library_paths: Vec<String>,
-    pub runtime_resource_path: String,
-}
+    fn get_target_info() -> SwiftTarget {
+        let swift_target_info_str = Command::new("swift")
+            .args(["-print-target-info"])
+            .output()
+            .unwrap()
+            .stdout;
 
-#[derive(Debug, Deserialize)]
-pub struct SwiftTarget {
-    pub target: SwiftTargetInfo,
-    pub paths: SwiftPaths,
-}
-
-pub fn get_swift_target_info() -> SwiftTarget {
-    let swift_target_info_str = Command::new("swift")
-        .args(["-print-target-info"])
-        .output()
-        .unwrap()
-        .stdout;
+        serde_json::from_slice(&swift_target_info_str).unwrap()
+    }
 
-    serde_json::from_slice(&swift_target_info_str).unwrap()
-}
+    pub fn configure() {
+        let swift_target_info = get_target_info();
+        if swift_target_info.target.libraries_require_rpath {
+            panic!("Libraries require RPath! Change minimum MacOS value to fix.")
+        }
 
-pub fn link_swift() {
-    let swift_target_info = get_swift_target_info();
-    if swift_target_info.target.libraries_require_rpath {
-        panic!("Libraries require RPath! Change minimum MacOS value to fix.")
+        swift_target_info
+            .paths
+            .runtime_library_paths
+            .iter()
+            .for_each(|path| {
+                println!("cargo:rustc-link-search=native={}", path);
+            });
     }
 
-    swift_target_info
-        .paths
-        .runtime_library_paths
-        .iter()
-        .for_each(|path| {
-            println!("cargo:rustc-link-search=native={}", path);
-        });
-}
+    pub fn link_package(package_name: &str, package_root: &str) {
+        let profile = env::var("PROFILE").unwrap();
 
-pub fn link_swift_package(package_name: &str, package_root: &str) {
-    let profile = env::var("PROFILE").unwrap();
-    dbg!(&profile);
+        if !Command::new("swift")
+            .args(["build", "-c", &profile])
+            .current_dir(package_root)
+            .status()
+            .unwrap()
+            .success()
+        {
+            panic!("Failed to compile swift package {}", package_name);
+        }
 
-    if !Command::new("swift")
-        .args(["build", "-c", &profile])
-        .current_dir(package_root)
-        .status()
-        .unwrap()
-        .success()
-    {
-        panic!("Failed to compile swift package {}", package_name);
+        let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+        let swift_target_info = get_target_info();
+        println!(
+            "cargo:rustc-link-search=native={}/{}.build/{}/{}",
+            manifest_dir, package_root, swift_target_info.target.unversioned_triple, profile
+        );
+        println!("cargo:rustc-link-lib=static={}", package_name);
     }
-
-    let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
-    let swift_target_info = get_swift_target_info();
-    println!(
-        "cargo:rustc-link-search=native={}/{}.build/{}/{}",
-        manifest_dir, package_root, swift_target_info.target.unversioned_triple, profile
-    );
-    println!("cargo:rustc-link-lib=static={}", package_name);
 }