ci : fix ios-xcode-build (ggml-org#15324)

* fix ios-xcode-build

* use xcode-select with fixed version

* switch to macos-15 to get xcode 16.4

Author: CISC

.github/workflows/build.yml

@@ -1113,6 +1113,11 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      - name: Setup Xcode
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: latest-stable
+
       - name: Build
         id: cmake_build
         run: |

.github/workflows/release.yml

@@ -600,14 +600,18 @@ jobs:
           name: llama-bin-win-hip-${{ matrix.name }}-x64.zip
 
   ios-xcode-build:
-    runs-on: macos-latest
+    runs-on: macos-15
 
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
+      - name: Setup Xcode
+        run: |
+          sudo xcode-select -s /Applications/Xcode_16.4.app
+
       - name: Build
         id: cmake_build
         run: |