Build MCU target packages only once for the target

... instead of once per host as well. Instead, download the slint compiler as needed.

.github/workflows/cpp_package.yaml

@@ -82,9 +82,8 @@ jobs:
  strategy:
  matrix:
  target: [thumbv7em-none-eabihf]
- host: [ubuntu-20.04, windows-2022, macOS-12]
 
- runs-on: ${{ matrix.host }}
+ runs-on: ubuntu-20.04
  steps:
  - uses: actions/checkout@v4
  - uses: ./.github/actions/install-linux-dependencies
@@ -108,7 +107,7 @@ jobs:
  with:
  cmakeListsOrSettingsJson: CMakeListsTxtAdvanced
  cmakeListsTxtPath: CMakeLists.txt
- cmakeAppendedArgs: "-GNinja -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_SHARED_LIBS=OFF -DRust_CARGO_TARGET=${{ matrix.target }} -DCMAKE_C_COMPILER=arm-none-eabi-gcc -DCMAKE_CXX_COMPILER=arm-none-eabi-g++ -DCMAKE_AR=arm-none-eabi-ar -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY ${{ env.SLINT_MCU_FEATURES }}"
+ cmakeAppendedArgs: "-GNinja -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_SHARED_LIBS=OFF -DRust_CARGO_TARGET=${{ matrix.target }} -DCMAKE_C_COMPILER=arm-none-eabi-gcc -DCMAKE_CXX_COMPILER=arm-none-eabi-g++ -DCMAKE_AR=arm-none-eabi-ar -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY -DSLINT_COMPILER=download ${{ env.SLINT_MCU_FEATURES }}"
  buildDirectory: ${{ runner.workspace }}/cppbuild
  buildWithCMakeArgs: "--config Release"
  - name: cpack
@@ -117,7 +116,7 @@ jobs:
  - name: "Upload C++ packages"
  uses: actions/upload-artifact@v4
  with:
- name: cpp_mcu_bin-${{ runner.os }}-${{ runner.arch }}-${{ matrix.target }}
+ name: cpp_mcu_bin-${{ matrix.target }}
  path: ${{ runner.workspace }}/cppbuild/Slint-cpp-*
 
  cmake_package_mcu_esp:
@@ -126,7 +125,6 @@ jobs:
  strategy:
  matrix:
  idf_target: [esp32s2, esp32s3, esp32p4]
- host: [ubuntu-22.04, macOS-12]
  include:
  - idf_target: esp32s2
  rust_target: xtensa-esp32s2-none-elf
@@ -135,7 +133,7 @@ jobs:
  - idf_target: esp32p4
  rust_target: riscv32imafc-esp-espidf
 
- runs-on: ${{ matrix.host }}
+ runs-on: ubuntu-22.04
  steps:
  - uses: actions/checkout@v4
  - uses: ./.github/actions/install-linux-dependencies
@@ -166,7 +164,7 @@ jobs:
  # NOTE: xtensa-esp-elf-gcc as compiler for the RISC-V targets is wrong, but the compiler argument here is only
  # used to ensure that SIZEOF_VOID_P is 4 in the generated cmake config file. Otherwise this build requires no
  # C compiler.
- cmakeAppendedArgs: "-GNinja -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF -DESP_PLATFORM=1 -DIDF_TARGET=${{ matrix.idf_target }} -DRust_CARGO_TARGET=${{ matrix.rust_target }} -DCMAKE_C_COMPILER=xtensa-esp-elf-gcc -DCMAKE_AR=xtensa-esp-elf-ar -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY -DSLINT_LIBRARY_CARGO_FLAGS='-Zbuild-std=core,alloc' ${{ env.SLINT_MCU_FEATURES }}"
+ cmakeAppendedArgs: "-GNinja -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF -DESP_PLATFORM=1 -DIDF_TARGET=${{ matrix.idf_target }} -DRust_CARGO_TARGET=${{ matrix.rust_target }} -DCMAKE_C_COMPILER=xtensa-esp-elf-gcc -DCMAKE_AR=xtensa-esp-elf-ar -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY -DSLINT_LIBRARY_CARGO_FLAGS='-Zbuild-std=core,alloc' -DSLINT_COMPILER=download ${{ env.SLINT_MCU_FEATURES }}"
  buildDirectory: ${{ runner.workspace }}/cppbuild
  buildWithCMakeArgs: "--config Release"
  - name: cpack
@@ -175,7 +173,7 @@ jobs:
  - name: "Upload C++ packages"
  uses: actions/upload-artifact@v4
  with:
- name: cpp_mcu_bin-${{ runner.os }}-${{ runner.arch }}-${{ matrix.idf_target }}
+ name: cpp_mcu_bin-${{ matrix.idf_target }}
  path: ${{ runner.workspace }}/cppbuild/Slint-cpp-*
 
  cmake_slint_compiler: