Use Travis addons.apt.packages to install packages

.travis.yml

@@ -16,6 +16,26 @@ env:
    #   via the "travis encrypt" command using the project repo's public key
    - secure: "jybGzAdUbqt9vWR/GEnRd96BgAi/7Zd1+2HK68j/i/8+/1YH2XxLOy4Jv/DUBhBlJIkxs/Xv8dRcUlFOclZDHX1d/9Qnsqd3oUVkD7k1y7cTOWy9TBQaE/v/kZo3LpzA3xPwwthrb0BvqIbOfIELi5fS5s8ba85WFRg3AX70wWE="
 addons:
+  apt:
+    sources:
+      - sourceline: 'ppa:openmw/openmw'
+      - ubuntu-toolchain-r-test
+      - llvm-toolchain-precise-3.6
+    packages: [
+      # Dev
+      clang-3.6, libunshield-dev, libtinyxml-dev,
+      # Tests
+      libgtest-dev, google-mock,
+      # Boost
+      libboost-filesystem-dev, libboost-program-options-dev, libboost-system-dev, libboost-thread-dev,
+      # FFmpeg
+      libavcodec-dev, libavformat-dev, libavutil-dev, libswscale-dev,
+      # Audio & Video
+      libsdl2-dev, libqt4-dev, libopenal-dev,
+      # The other from OpenMW ppa
+      libbullet-dev, libswresample-dev, libopenscenegraph-dev, libmygui-dev
+    ]
+
   coverity_scan:
     project:
       name: "OpenMW/openmw"

CI/before_install.linux.sh

@@ -1,18 +1,6 @@
 #!/bin/sh
 
-if [ "${ANALYZE}" ]; then
+# build libgtest & libgtest_main
-  echo "yes" | sudo add-apt-repository "deb http://llvm.org/apt/`lsb_release -sc`/ llvm-toolchain-`lsb_release -sc`-3.6 main"
-  wget -O - http://llvm.org/apt/llvm-snapshot.gpg.key|sudo apt-key add -
-fi
-
-echo "yes" | sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu `lsb_release -sc` main universe restricted multiverse"
-echo "yes" | sudo apt-add-repository ppa:openmw/openmw
-sudo apt-get update -qq
-sudo apt-get install -qq libgtest-dev google-mock
-sudo apt-get install -qq libboost-filesystem-dev libboost-program-options-dev libboost-system-dev libboost-thread-dev
-sudo apt-get install -qq libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libswresample-dev
-sudo apt-get install -qq libbullet-dev libopenscenegraph-dev libmygui-dev libsdl2-dev libunshield-dev libtinyxml-dev libopenal-dev libqt4-dev
-if [ "${ANALYZE}" ]; then sudo apt-get install -qq clang-3.6; fi
 sudo mkdir /usr/src/gtest/build
 cd /usr/src/gtest/build
 sudo cmake .. -DBUILD_SHARED_LIBS=1