ci : upload xcframework artifact from ios-xcode-build job (ggml-org#16010)

This commit updates the github workflows build.yml file to include steps
for uploading and downloading the xcframework artifact. The
macos-latest-swift job now depends on the ios-xcode-build job and
downloads the xcframework artifact produced by it.

The motivation for this changes is that it takes a long time to build
the xcframework and we are currently doing this twice in the workflow.
With this change, we only build it once and reuse the artifact.

Author: danbev

.github/workflows/build.yml

@@ -711,6 +711,7 @@ jobs:
 
   macOS-latest-swift:
     runs-on: macos-latest
+    needs: ios-xcode-build
 
     strategy:
       matrix:
@@ -727,6 +728,12 @@ jobs:
           key: macOS-latest-swift
           evict-old-files: 1d
 
+      - name: Download xcframework artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: llama-xcframework
+          path: build-apple/llama.xcframework/
+
       - name: Dependencies
         id: depends
         continue-on-error: true
@@ -748,11 +755,6 @@ jobs:
             -DCMAKE_OSX_ARCHITECTURES="arm64;x86_64"
           cmake --build build --config Release -j $(sysctl -n hw.logicalcpu)
 
-      - name: xcodebuild for swift package
-        id: xcodebuild
-        run: |
-          ./build-xcframework.sh
-
   windows-msys2:
     runs-on: windows-2025
 
@@ -1170,6 +1172,13 @@ jobs:
         run: |
           ./build-xcframework.sh
 
+      - name: Upload xcframework artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: llama-xcframework
+          path: build-apple/llama.xcframework/
+          retention-days: 1
+
       - name: Build Xcode project
         run: |
           xcodebuild -downloadPlatform iOS