Maybe needs libglew-dev?

.travis.yml

@@ -4,7 +4,7 @@ compiler:
 before_install:
  - sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
  - sudo apt-get -qq update
- - sudo apt-get -qq install g++-4.8 xorg-dev libglu1-mesa-dev
+ - sudo apt-get -qq install g++-4.8 xorg-dev libglu1-mesa-dev libglew-dev
  - sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 90
  - git clone https://github.com/glfw/glfw.git
  - "mkdir glfw/build && cd glfw/build && cmake .. && make && sudo make install ; cd -"