Feature: Build macOS build as a universal binary

.github/workflows/release.yml

@@ -362,12 +362,6 @@ jobs:
 
     strategy:
       fail-fast: false
-      matrix:
-        include:
-        - arch: x64
-          full_arch: x86_64
-        - arch: arm64
-          full_arch: arm64
 
     runs-on: macos-10.15
     env:
@@ -397,8 +391,7 @@ jobs:
         vcpkgDirectory: '/usr/local/share/vcpkg'
         doNotUpdateVcpkg: false
         vcpkgGitCommitId: 2a42024b53ebb512fb5dd63c523338bf26c8489c
-        vcpkgArguments: 'freetype liblzma lzo'
-        vcpkgTriplet: '${{ matrix.arch }}-osx'
+        vcpkgArguments: 'freetype:x64-osx liblzma:x64-osx lzo:x64-osx freetype:arm64-osx liblzma:arm64-osx lzo:arm64-osx'
 
     - name: Build tools
       run: |
@@ -430,15 +423,35 @@ jobs:
       # If this is run on a fork, there may not be a certificate set up - continue in this case
       continue-on-error: true
 
-    - name: Build
+    - name: Build arm64
+      run: |
+        mkdir build-arm64
+        cd build-arm64
+
+        echo "::group::CMake"
+        cmake ${GITHUB_WORKSPACE} \
+          -DCMAKE_OSX_ARCHITECTURES=arm64 \
+          -DVCPKG_TARGET_TRIPLET=arm64-osx \
+          -DCMAKE_TOOLCHAIN_FILE=/usr/local/share/vcpkg/scripts/buildsystems/vcpkg.cmake \
+          -DHOST_BINARY_DIR=${GITHUB_WORKSPACE}/build-host \
+          -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+          # EOF
+        echo "::endgroup::"
+
+        echo "::group::Build"
+        echo "Running on $(sysctl -n hw.logicalcpu) cores"
+        make -j$(sysctl -n hw.logicalcpu)
+        echo "::endgroup::"
+
+    - name: Build x86_64
       run: |
         mkdir build
         cd build
 
         echo "::group::CMake"
         cmake ${GITHUB_WORKSPACE} \
-          -DCMAKE_OSX_ARCHITECTURES=${{ matrix.full_arch }} \
-          -DVCPKG_TARGET_TRIPLET=${{ matrix.arch }}-osx \
+          -DCMAKE_OSX_ARCHITECTURES=x86_64 \
+          -DVCPKG_TARGET_TRIPLET=x64-osx \
           -DCMAKE_TOOLCHAIN_FILE=/usr/local/share/vcpkg/scripts/buildsystems/vcpkg.cmake \
           -DHOST_BINARY_DIR=${GITHUB_WORKSPACE}/build-host \
           -DCMAKE_BUILD_TYPE=RelWithDebInfo \
@@ -456,6 +469,23 @@ jobs:
         # the end of this workflow.
         rm -f bundles/*.sha256
 
+    - name: Build package
+      run: |
+        cd build
+
+        # Combine the `openttd` binaries from each build into a single file
+        mv openttd openttd-x64
+        lipo -create -output openttd openttd-x64 ../build-arm64/openttd
+
+        echo "::group::Build"
+        echo "Running on $(sysctl -n hw.logicalcpu) cores"
+        make -j$(sysctl -n hw.logicalcpu) package
+        echo "::endgroup::"
+
+        # Remove the sha256 files CPack generates; we will do this ourself at
+        # the end of this workflow.
+        rm -f bundles/*.sha256
+
     - name: Install gon
       env:
         HOMEBREW_NO_AUTO_UPDATE: 1
@@ -475,7 +505,7 @@ jobs:
     - name: Store bundles
       uses: actions/upload-artifact@v2
       with:
-        name: openttd-macos-${{ matrix.arch }}
+        name: openttd-macos-universal
         path: build/bundles
         retention-days: 5