Add a GHActions workflow using MacOS 11

Author: suve

.github/workflows/ci.yml

@@ -7,6 +7,27 @@ on:
     branches: [ master ]
 
 jobs:
+  macos-11:
+    runs-on: macos-11
+    steps:
+      - name: Install FPC
+        run: |
+          brew update
+          brew install fpc
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Compile SDL2 unit
+        run: fpc sdl2.pas
+      - name: Compile SDL2_gfx unit
+        run: fpc sdl2_gfx.pas
+      - name: Compile SDL2_image unit
+        run: fpc sdl2_image.pas
+      - name: Compile SDL2_mixer unit
+        run: fpc sdl2_mixer.pas
+      - name: Compile SDL2_net unit
+        run: fpc sdl2_net.pas
+      - name: Compile SDL2_ttf unit
+        run: fpc sdl2_ttf.pas
   ubuntu-20-04:
     runs-on: ubuntu-20.04
     steps: