Switch macOS CI runners from macos-15 to macos-latest

macOS 15 SDK compiles MLX C++ with @available() checks that reference
___isPlatformVersionAtLeast from the compiler runtime, causing linker
errors. macOS 14 (macos-latest) does not have this issue. This matches
qwen3_asr_rs which also uses macos-latest.

Signed-off-by: Michael Yuan <michael@secondstate.io>
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Michael Yuan <michael@secondstate.io>

Author: juntao

.github/workflows/ci.yml

@@ -210,7 +210,7 @@ jobs:
   # ───────────────────────────────────────────────────────────────────────────
   macos-mlx:
     name: macOS Apple Silicon (mlx)
-    runs-on: macos-15   # macOS 15 on Apple Silicon (M-series)
+    runs-on: macos-latest   # macOS 14+ on Apple Silicon (M-series)
 
     steps:
       - uses: actions/checkout@v4

.github/workflows/integration-test.yml

@@ -301,7 +301,7 @@ jobs:
   # ─────────────────────────────────────────────────────────────────────────────
   test-macos-mlx:
     name: Integration — macOS Apple Silicon (mlx)
-    runs-on: macos-15
+    runs-on: macos-latest
     if: |
       always() && (
         github.event_name == 'schedule' ||

.github/workflows/release.yml

@@ -95,7 +95,7 @@ jobs:
               https://github.com/second-state/libtorch-releases/releases/download/v2.7.1/libtorch-cxx11-abi-aarch64-cuda12.6-2.7.1.tar.gz
 
           # ── macOS Apple Silicon — MLX backend ────────────────────────────
-          - os: macos-15
+          - os: macos-latest
             name: macOS Apple Silicon
             backend: mlx
             asset-name: transcribe-macos-aarch64

build.rs

@@ -88,15 +88,6 @@ fn build_mlx() {
     // C++ standard library (MLX is C++)
     println!("cargo:rustc-link-lib=c++");
 
-    // Set the minimum macOS deployment target for the linker.
-    // MLX C++ code uses @available() checks that reference ___isPlatformVersionAtLeast
-    // from the compiler runtime. The Rust linker must target the same (or higher)
-    // macOS version so the runtime is linked.
-    println!(
-        "cargo:rustc-link-arg=-mmacosx-version-min={}",
-        deployment_target
-    );
-
     // Rerun if mlx-c sources change
     println!("cargo:rerun-if-changed=mlx-c/CMakeLists.txt");
     println!("cargo:rerun-if-changed=build.rs");