Another try for Travis Linux :/

CMakeLists.txt

-cmake_minimum_required (VERSION 2.8)
+cmake_minimum_required (VERSION 2.8.8)
 project (OpenRaider)
 
 # Version Number

cmake/travis_install_linux.sh

 #!/bin/bash
 
-sudo apt-get -qq -y install libsdl2-dev libsdl2-ttf-dev libalut-dev libpng12-dev zlib1g-dev
+sudo apt-get -qq -y install libsdl2-dev libsdl2-ttf-dev libalut-dev libpng12-dev zlib1g-dev cmake
 if [ "$CC" = "gcc" ]; then sudo apt-get install gcc-4.8; fi
 if [ "$CXX" = "g++" ]; then sudo apt-get install g++-4.8; fi
 

cmake/travis_script_linux.sh

 if [ "$CC" = "gcc" ]; then export CC="gcc-4.8"; fi
 if [ "$CXX" = "g++" ]; then export CXX="g++-4.8"; fi
 
-mkdir build && cd build && cmake .. && make
+mkdir build && cd build && cmake .. && make && make check
 

cmake/travis_script_mac.sh

 #!/bin/bash
 
-mkdir build && cd build && cmake .. && make
+mkdir build && cd build && cmake .. && make && make check