WIP: github: Test on macos-14, -15 and -26

.github/workflows/build.yml

@@ -185,7 +185,14 @@ jobs:
   # Build a cross compiler for macOS, targeting Windows.
   macos:
     needs: [prepare]
-    runs-on: macos-14
+    strategy:
+      fail-fast: false
+      matrix:
+        runner:
+          - macos-14
+          - macos-15
+          - macos-26
+    runs-on: ${{matrix.runner}}
     steps:
       - uses: actions/checkout@v4
       - name: Build
@@ -211,7 +218,7 @@ jobs:
           gtar -Jcf ../$NAME.tar.xz --format=ustar --numeric-owner --owner=0 --group=0 --sort=name --mtime="$BUILD_DATE" $NAME
       - uses: actions/upload-artifact@v4
         with:
-          name: macos-ucrt-toolchain
+          name: ${{matrix.runner}}-ucrt-toolchain
           path: |
             llvm-mingw-*.tar.xz
           retention-days: 7