feat(gx): add incomplete 'CGxDeviceGLSDL' (#2)

* chore(build): add vendored SDL 3.0.0 library

* chore(build): add vendored glew-cmake-2.2.0 library

* feat(console): in the presence of -opengl launch flag, change GxApi to OpenGl

* feat(gx): add uncompleted CGxDeviceGLSDL targeting Windows and Linux

* chore(build): change SDL3 linkage from shared (bad) to to static (good)

vendor/sdl-3.0.0/.github/workflows/riscos.yml

@@ -0,0 +1,64 @@
+name: Build (RISC OS)
+
+on: [push, pull_request]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  Build:
+    name: ${{ matrix.platform.name }}
+    runs-on: ubuntu-latest
+    container: riscosdotinfo/riscos-gccsdk-4.7:latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        platform:
+          - { name: CMake }
+
+    steps:
+    - name: Setup dependencies
+      run: apt-get update && apt-get install -y cmake ninja-build
+    - uses: actions/checkout@v3
+    - name: Configure (CMake)
+      if: ${{ contains(matrix.platform.name, 'CMake') }}
+      run: |
+        cmake -S . -B build -G Ninja \
+          -Wdeprecated -Wdev -Werror \
+          -DCMAKE_TOOLCHAIN_FILE=/home/riscos/env/toolchain-riscos.cmake \
+          -DCMAKE_DISABLE_PRECOMPILE_HEADERS=ON \
+          -DRISCOS:BOOL=ON \
+          -DSDL_GCC_ATOMICS=OFF \
+          -DSDL_TESTS=ON \
+          -DSDL_INSTALL_TESTS=ON \
+          -DSDL_VENDOR_INFO="Github Workflow" \
+          -DCMAKE_BUILD_TYPE=Release \
+          -DCMAKE_INSTALL_PREFIX=${{ github.workspace }}/prefix_cmake
+    - name: Build (CMake)
+      if: ${{ contains(matrix.platform.name, 'CMake') }}
+      run: cmake --build build --verbose
+    - name: Install (CMake)
+      if: ${{ contains(matrix.platform.name, 'CMake') }}
+      run: |
+        echo "SDL3_DIR=${{ github.workspace }}/prefix_cmake" >> $GITHUB_ENV
+        cmake --install build/
+        ( cd ${{ github.workspace }}/prefix_cmake; find ) | LC_ALL=C sort -u
+    - name: Package (CPack)
+      run: |
+        cmake --build build/ --config Release --target package
+    - name: Verify CMake configuration files
+      run: |
+        cmake -S cmake/test -B cmake_config_build -G Ninja \
+          -DTEST_SHARED=OFF \
+          -DCMAKE_TOOLCHAIN_FILE=/home/riscos/env/toolchain-riscos.cmake \
+          -DCMAKE_PREFIX_PATH=${{ env.SDL3_DIR }} \
+          -DCMAKE_BUILD_TYPE=Release \
+          ${{ matrix.platform.test_args }}
+        cmake --build cmake_config_build --verbose
+    - uses: actions/upload-artifact@v3
+      with:
+        if-no-files-found: error
+        name: SDL-riscos
+        path: build/dist/SDL3*