Add github action to do CI checks against macOS

Author: Hannes Steffenhagen

.github/workflows/pull-request-checks.yaml

@@ -0,0 +1,35 @@
+# This is a basic workflow to help you get started with Actions
+
+name: pull-request-checks
+on:
+  pull_request:
+    branches: [ develop ]
+
+# A workflow run is made up of one or more jobs that can run sequentially or in parallel
+jobs:
+  check-macos-10_15-cmake-clang:
+    runs-on: macos-10.15
+    env:
+      # CCache maximum size shouldn't be too big
+      # because we have a global cache limit of 5G.
+      # Full CProver uses about 100MB of cache,
+      # we'll keep 5 times that around per OS
+      # to account for different versions/different
+      # flags
+      # Bump so CI runs again 2
+      CCACHE_MAXSIZE: 500Mi
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          submodules: true
+      - name: Fetch dependencies
+        run: brew install cmake ninja maven flex bison
+      - name: Configure using CMake
+        run: |
+          mkdir build
+          cd build
+          cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=/usr/bin/clang -DCMAKE_CXX_COMPILER=/usr/bin/clang++
+      - name: Build with Ninja
+        run: cd build; ninja
+      - name: Run CTest
+        run: cd build; ctest -V -L CORE .