Add using dockerfiles based on the LTS and BRANCH env vars

This makes it simpler in the future to have branches that have dependencies that are different from master, rather than having a single image with all necessary dependencies installed, which may at some point end up not being possible to do.

(cherry-picked from commit 1bb5fdf283)

.travis.yml

@@ -12,19 +12,19 @@ cache:
 matrix:
   include:
     - compiler: gcc
-      env: TOOL=scons CXXSTD=14 NLS=true
+      env: TOOL=scons CXXSTD=14 NLS=true LTS=1604 BRANCH=master
 
     - compiler: gcc
-      env: TOOL=scons CXXSTD=14 NLS=false OPT=-O0
+      env: TOOL=scons CXXSTD=14 NLS=false LTS=1604 BRANCH=master OPT=-O0
 
     - compiler: gcc
-      env: TOOL=cmake CXXSTD=14 NLS=false
+      env: TOOL=cmake CXXSTD=14 NLS=false LTS=1604 BRANCH=master
 
     - compiler: clang
-      env: TOOL=scons CXXSTD=14 NLS=false OPT=-O0
+      env: TOOL=scons CXXSTD=14 NLS=false LTS=1604 BRANCH=master OPT=-O0
 
     - compiler: clang
-      env: TOOL=cmake CXXSTD=14 NLS=false
+      env: TOOL=cmake CXXSTD=14 NLS=false LTS=1604 BRANCH=master
 
     - os: osx
       compiler: clang

docker/Dockerfile-travis-1604-master

@@ -1,4 +1,4 @@
-FROM wesnoth/wesnoth:16.04
+FROM wesnoth/wesnoth:1604-master
 
 COPY ./ /home/wesnoth-travis/
 

utils/travis/steps/install.sh

@@ -30,5 +30,5 @@ if [ "$TRAVIS_OS_NAME" = "osx" ]; then
         export LDFLAGS="-L/usr/local/opt/openssl/lib $LDFLAGS"
     fi
 else
-    docker build -t wesnoth-repo:16.04 -f docker/Dockerfile-travis .
+    docker build -t wesnoth-repo:"$LTS"-"$BRANCH" -f docker/Dockerfile-travis-"$LTS"-"$BRANCH" .
 fi

utils/travis/steps/script.sh

@@ -33,7 +33,7 @@ if [ "$TRAVIS_OS_NAME" = "osx" ]; then
     fi
 else
     docker run -v "$HOME"/build-cache:/home/wesnoth-travis/build \
-               -v "$HOME"/.ccache:/root/.ccache wesnoth-repo:16.04 \
+               -v "$HOME"/.ccache:/root/.ccache wesnoth-repo:"$LTS"-"$BRANCH" \
                bash -c './utils/travis/docker_run.sh "$@"' \
                bash "$NLS" "$TOOL" "$CC" "$CXX" "$CXXSTD" "$EXTRA_FLAGS_RELEASE" "$WML_TESTS" "$WML_TEST_TIME" "$PLAY_TEST" "$MP_TEST" "$BOOST_TEST" "$LTO"
 fi