Add CI pipeline

[TheCodez]

• [x] Ubuntu building
• [ ] Windows building

[TheCodez]

@cbachhuber not including the demo project in the build links successfully. So the problem should stem from the demo project.

[cbachhuber]

Right, I already found that as well. I'm quite sure, however, that not the demo project is the problem, but that we are linking everything together to an executable. So at this time, 'undefined reference' errors will surface.

I had the suspicion that CI does not find the GLEW library, and I'm right:

• I added printing of variable GLEW_LIBRARY in this commit.
• On my machine, I see during configuration

  -- GLEW LIBRARY LOCATION: 
  -- /usr/lib/x86_64-linux-gnu/libGLEW.so
  

• On CI, I see

   -- GLEW LIBRARY LOCATION: 
   --
  

So I'm currently looking into ways of enabling CI to find GLEW. Do you think that makes sense?

[cbachhuber]

Fixed! See this build :)

[cbachhuber]

This answer writes GLEW_LIBRARIES instead of GLEW_LIBRARY. Also cmake documentation promotes GLEW_LIBRARIES. So I used that, and it works :)

PR incoming ;)

[TheCodez]

Thanks you for testing this. I just pushed a commit to see if GLEW_LIBRARIES is the only change needed. So I guess no need for a PR but thanks a lot 👍 I just saw you also did some cleanup so a PR is fine of course.

[cbachhuber]

It seems that something else is needed. I just created a new branch, but with only the GLEW_LIBRARIES change it does not compile. I suggest that I clean up branch fix-ci and create a PR. Ok?

[TheCodez]

Sure go ahead 👍 . I suggest rebasing against my master branch as I have removed the build folder. So it has to be created again in the CI.