use ubuntu 16.04 for CI builds

language: cpp

compiler: clang

dist: trusty

compiler: gcc

dist: xenial

env:

  - CXXFLAGS="-stdlib=libc++"

before_install:

  - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test

  - sudo apt-get update -qq

  - sudo apt-get install -y gcc-8 g++-8 cmake libcairo2-dev libharfbuzz-dev libfreetype6-dev

  - sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-8 90

script:

  - cmake .

  - make all test CTEST_OUTPUT_ON_FAILURE=1

before_install:

  - sudo apt-get -qq update

  - sudo apt-get install -y libc++-dev cmake libcairo2-dev libharfbuzz-dev libfreetype6-dev