Github Actions caching. [ci skip]

.github/workflows/ci-main.yml

@@ -15,6 +15,13 @@ jobs:
         with:
           submodules: "true"
 
+      - name: Cache object files
+        uses: actions/cache@v2
+        env:
+          cache-name: linux-01-cache
+        with:
+          path: ~/build-cache
+          key: linux-01
+
       - name: Ubuntu 20.04 - scons, gcc, LTO, unit tests
-        run: |
-          ./.github/workflows/ci-scripts/ubuntu.sh
+        run: ./.github/workflows/ci-scripts/ubuntu.sh

.github/workflows/ci-scripts/docker.sh

@@ -5,8 +5,6 @@ scons wesnoth wesnothd campaignd boost_unit_tests build=release \
     extra_flags_config="-pipe" strict=true forum_user_handler=true \
     nls=false enable_lto=true sanitize="" jobs=2 --debug=time
 
-ls -Al
-
 # set the fake display for unit tests
 export DISPLAY=:99.0
 /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -ac -screen 0 1024x768x24

.github/workflows/ci-scripts/ubuntu.sh

@@ -2,14 +2,12 @@
 
 date
 
-docker image ls
-
 echo FROM wesnoth/wesnoth:2004-master > utils/dockerbuilds/travis/Dockerfile-travis-2004-master
 echo COPY ./ /home/wesnoth-travis/ >> utils/dockerbuilds/travis/Dockerfile-travis-2004-master
 echo WORKDIR /home/wesnoth-travis >> utils/dockerbuilds/travis/Dockerfile-travis-2004-master
 
 docker build -t wesnoth-repo:2004-master -f utils/dockerbuilds/travis/Dockerfile-travis-2004-master .
 
-docker image ls
-
-docker run --cap-add=ALL --privileged wesnoth-repo:2004-master ./.github/workflows/ci-scripts/docker.sh
+docker run --cap-add=ALL --privileged \
+    --volume ~/build-cache:/home/wesnoth-travis/build \
+    wesnoth-repo:2004-master ./.github/workflows/ci-scripts/docker.sh