ci: Use libsdl-org/setup-sdl to make SDL2 available on all platforms.

.github/workflows/main.yml

@@ -8,16 +8,16 @@ jobs:
     runs-on: ${{ matrix.platform.os }}
     strategy:
       matrix:
-        platform:  # !!! FIXME: figure out an efficient way to get SDL2 on the Windows/Mac bots.
-        - { name: Linux,   os: ubuntu-20.04, flags: -GNinja }
-        #- { name: Windows, os: windows-latest }
-        #- { name: MacOS,   os: macos-latest }
+        platform:
+        - { name: Linux,   os: ubuntu-latest }
+        - { name: Windows, os: windows-latest }
+        - { name: MacOS,   os: macos-latest }
     steps:
-    - name: Setup Linux dependencies
-      if: runner.os == 'Linux'
-      run: |
-        sudo apt-get update
-        sudo apt-get install cmake ninja-build libsdl2-dev
+    - name: Set up SDL
+      id: sdl
+      uses: libsdl-org/setup-sdl@main
+      with:
+        version: sdl2-latest
     - name: Get MojoAL sources
       uses: actions/checkout@v2
     - name: Configure CMake

CMakeLists.txt

@@ -1,8 +1,8 @@
 # YOU PROBABLY DON'T HAVE TO USE THIS CMAKE PROJECT, IT'S JUST A SINGLE
 #  C FILE. COPY IT INTO YOUR PROJECT INSTEAD.
 
+cmake_minimum_required(VERSION 3.12.0)
 project(mojoAL)
-cmake_minimum_required(VERSION 3.0.0)
 
 find_package(SDL2 REQUIRED)