ci: add separate Darwin build targets for libghostty-vt

.github/workflows/test.yml

@@ -252,6 +252,34 @@ jobs:
             -Dtarget=${{ matrix.target }} \
             -Dsimd=false
 
+  # lib-vt requires macOS runner for macOS/iOS builds becauase it requires the `apple_sdk` path
+  build-libghostty-vt-macos:
+    strategy:
+      matrix:
+        target: [aarch64-macos, x86_64-macos, aarch64-ios]
+    runs-on: namespace-profile-ghostty-macos-tahoe
+    needs: test
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      # TODO(tahoe): https://github.com/NixOS/nix/issues/13342
+      - uses: DeterminateSystems/nix-installer-action@main
+        with:
+          determinate: true
+      - uses: cachix/cachix-action@3ba601ff5bbb07c7220846facfa2cd81eeee15a1 # v16
+        with:
+          name: ghostty
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+
+      - name: Xcode Select
+        run: sudo xcode-select -s /Applications/Xcode_26.2.app
+
+      - name: Build
+        run: |
+          nix develop -c zig build lib-vt \
+            -Dtarget=${{ matrix.target }}
+
   build-linux:
     strategy:
       fail-fast: false