Merge pull request #467 from Interlisp/sdl

Bring SDL into master branch

.github/workflows/build.yml

@@ -42,9 +42,17 @@ jobs:
       BUILD_TYPE: Release
     steps:
     - uses: actions/checkout@v3
+    - name: Show CMake version
+      run: cmake --version
     - name: Install X11 dependencies on MacOS
       if: ${{ runner.os == 'macOS'}}
       run: brew install --cask xquartz
+    - name: Install SDL2 dependencies on MacOS
+      if: ${{ runner.os == 'macOS'}}
+      run: brew install sdl2
+    - name: Install SDL dependency on Ubuntu
+      if: ${{ runner.os == 'Linux'}}
+      run: sudo apt-get update && sudo apt-get install -y libsdl2-dev
     - name: Create Build Environment
       run: cmake -E make_directory ${{github.workspace}}/build
     - name: Configure CMake