CI: Add a nightly arm64 linux CI build

This requires setting VCPKG_FORCE_SYSTEM_BINARIES to 1, per vcpkg
documentation.

.github/actions/setup/action.yml

@@ -40,6 +40,8 @@ runs:
         sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-13 100
         sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-13 100
 
+        # FIXME: https://github.com/WebAssembly/wabt/issues/2533
+        #        wabt doesn't have binary releases for arm64 Linux
         wget https://github.com/WebAssembly/wabt/releases/download/1.0.35/wabt-1.0.35-ubuntu-20.04.tar.gz
         tar -xzf ./wabt-1.0.35-ubuntu-20.04.tar.gz
         rm ./wabt-1.0.35-ubuntu-20.04.tar.gz
@@ -59,6 +61,13 @@ runs:
         brew update
         brew install autoconf autoconf-archive automake bash ccache coreutils llvm@19 nasm ninja qt unzip wabt
 
+    - name: 'Set required environment variables'
+      if: ${{ inputs.os == 'Linux' && inputs.arch == 'arm64' }}
+      uses: actions/github-script@v7
+      with:
+        script: |
+          core.exportVariable('VCPKG_FORCE_SYSTEM_BINARIES', '1')
+
     - name: 'Install vcpkg'
       shell: bash
       run: ./Toolchain/BuildVcpkg.sh

.github/workflows/lagom-template.yml

@@ -82,7 +82,14 @@ jobs:
             echo "cmake_options=-DENABLE_CLANG_PLUGINS=ON" >> "$GITHUB_OUTPUT"
           else
             echo "ccache_key=${{ inputs.build_preset }}" >> "$GITHUB_OUTPUT"
-            echo "cmake_options=" >> "$GITHUB_OUTPUT"
+            if ${{ inputs.os_name == 'Linux' && inputs.arch == 'arm64' }} ; then
+                # FIXME: https://github.com/WebAssembly/wabt/issues/2533
+                #        wabt doesn't have binary releases for arm64 Linux
+                PKGCONFIG=$(which pkg-config)
+                echo "cmake_options=-DPKG_CONFIG_EXECUTABLE=$PKGCONFIG" >> "$GITHUB_OUTPUT"
+            else
+              echo "cmake_options=-DINCLUDE_WASM_SPEC_TESTS=ON -DWASM_SPEC_TEST_SKIP_FORMATTING=ON" >> "$GITHUB_OUTPUT"
+            fi
           fi
 
       - name: Restore Caches
@@ -112,8 +119,6 @@ jobs:
         working-directory: ${{ github.workspace }}
         run: |
           cmake --preset ${{ inputs.build_preset }} -B Build \
-            -DINCLUDE_WASM_SPEC_TESTS=ON \
-            -DWASM_SPEC_TEST_SKIP_FORMATTING=ON \
             ${{ steps.build-parameters.outputs.cmake_options }} \
             -DPython3_EXECUTABLE=${{ env.pythonLocation }}/bin/python \
             -DCMAKE_C_COMPILER=${{ steps.build-parameters.outputs.host_cc }} \

.github/workflows/nightly-lagom.yml

@@ -0,0 +1,34 @@
+name: Nightly Lagom
+
+on:
+  # Automatically run at the end of every day.
+  schedule:
+    - cron: '0 0 * * *'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  # CI matrix - runs the job in lagom-template.yml with different configurations.
+  Lagom:
+    if: github.repository == 'LadybirdBrowser/ladybird'
+
+    strategy:
+      fail-fast: false
+      matrix:
+        os_name: ['Linux']
+        os: [ubuntu-24.04-arm]
+        arch: ['arm64']
+        build_preset: ['Sanitizer_CI']
+        toolchain: ['Clang']
+        clang_plugins: [false]
+
+    uses: ./.github/workflows/lagom-template.yml
+    with:
+      toolchain: ${{ matrix.toolchain }}
+      os_name: ${{ matrix.os_name }}
+      os: ${{ matrix.os }}
+      arch: ${{ matrix.arch }}
+      build_preset: ${{ matrix.build_preset }}
+      clang_plugins: ${{ matrix.clang_plugins }}