ci attempt to speed up cross tests

.github/workflows/ccpp.yml

@@ -55,6 +55,12 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2.1.0
+      - name: Setup cache
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.ccache
+          key: lvgl_ci_cross_test_ccache_${{ matrix.arch }}
       - uses: uraimo/run-on-arch-action@v2.1.1
         name: Run tests
         id: build
@@ -68,10 +74,19 @@ jobs:
           # The shell to run commands with in the container
           shell: /bin/bash
           
+          # Create cached/volume directories on host
+          setup: |
+            mkdir -p ~/.ccache
+
+          # Mount cached directories in the container for faster builds
+          dockerRunArgs: |
+            --volume "${HOME}/.ccache:/root/.ccache"
+
           install: |
             apt-get update -y
-            apt-get install -y gcc python3 libpng-dev ruby-full gcovr cmake
+            apt-get install build-essential ccache python3 libpng-dev ruby-full gcovr cmake -q -y
-            apt-get install -y build-essential
+            /usr/sbin/update-ccache-symlinks
+            echo 'export PATH="/usr/lib/ccache:$PATH"' | tee -a ~/.bashrc
 
           run: |
-            env ASAN_OPTIONS=detect_leaks=0 python3 tests/main.py --report test
+            env ASAN_OPTIONS=detect_leaks=0 python3 tests/main.py test