WIP: Attempt to build MCU binary package

For now with configs for stm32, but esp-idf variants (xtensa, riscv) also to be added.

.github/workflows/cpp_package.yaml

@@ -11,9 +11,10 @@ env:
     MACOSX_DEPLOYMENT_TARGET: "11.0"
     # Keep in sync with features in nightly_snapshot.yaml, slint_tool_binary.yaml, api/node/Cargo.toml, and api/python/Cargo.toml
     SLINT_BINARY_FEATURES: "-DSLINT_FEATURE_BACKEND_LINUXKMS_NOSEAT=ON -DSLINT_FEATURE_BACKEND_WINIT=ON -DSLINT_FEATURE_RENDERER_FEMTOVG=ON -DSLINT_FEATURE_RENDERER_SKIA=ON -DSLINT_FEATURE_RENDERER_SOFTWARE=ON"
+    SLINT_MCU_FEATURES: "-DSLINT_FEATURE_FREESTANDING=ON -DSLINT_FEATURE_RENDERER_SOFTWARE=ON"
 
 jobs:
-    cmake_package:
+    cmake_package_desktop:
         env:
             DYLD_FRAMEWORK_PATH: /Users/runner/work/slint/Qt/6.5.1/clang_64/lib
             QT_QPA_PLATFORM: offscreen
@@ -70,3 +71,54 @@ jobs:
               with:
                   name: cpp_bin-${{ matrix.package_suffix }}
                   path: ${{ runner.workspace }}/cppbuild/Slint-cpp-*
+
+    cmake_package_mcu:
+        env:
+            CARGO_INCREMENTAL: false
+        strategy:
+            matrix:
+                target: [thumbv7em-none-eabihf]
+                host: [ubuntu-20.04, windows-2022, macOS-12]
+                include:
+                    - os: ubuntu-20.04
+                      package_suffix: linux
+                    - os: macOS-12
+                      package_suffix: macos
+                    - os: windows-2022
+                      package_suffix: windows
+
+        runs-on: ${{ matrix.os }}
+        steps:
+            - uses: actions/checkout@v4
+            - uses: ./.github/actions/install-linux-dependencies
+              with:
+                  old-ubuntu: true
+            - uses: ./.github/actions/setup-rust
+            - uses: baptiste0928/cargo-install@v3
+              with:
+                  crate: cargo-about
+            - name: Prepare licenses
+              run: bash -x ../../scripts/prepare_binary_package.sh ../..
+              working-directory: api/cpp/
+            - uses: ilammy/msvc-dev-cmd@v1
+            - name: Select MSVC (windows)
+              run: |
+                  echo "CC=cl.exe" >> $GITHUB_ENV
+                  echo "CXX=cl.exe" >> $GITHUB_ENV
+              if: matrix.os == 'windows-2022'
+            - name: C++ Build
+              uses: lukka/[email protected]
+              with:
+                  cmakeListsOrSettingsJson: CMakeListsTxtAdvanced
+                  cmakeListsTxtPath: CMakeLists.txt
+                  cmakeAppendedArgs: "-DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF ${{ env.SLINT_MCU_FEATURES }} "
+                  buildDirectory: ${{ runner.workspace }}/cppbuild
+                  buildWithCMakeArgs: "--config Release"
+            - name: cpack
+              working-directory: ${{ runner.workspace }}/cppbuild
+              run: cpack -G TGZ -DCPACK_SYSTEM_NAME=${{ runner.os }}-${{ runner.arch }}-${{ matrix.target }}
+            - name: "Upload C++ packages"
+              uses: actions/upload-artifact@v4
+              with:
+                  name: cpp_mcu_bin-${{ runner.os }}-${{ runner.arch }}-${{ matrix.target }}
+                  path: ${{ runner.workspace }}/cppbuild/Slint-cpp-*