Try to fix when git pulls a rebased branch again

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@2719 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9
supertux has an option for a gles renderer, instead of using X based GLEW (which crashes on Wayland)

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@2720 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9
Allow Supertux gl as well, now that it compiles and runs.

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@2721 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9
drop glbinding, it's a bit slower, and it makes the supertux2 binary larger...

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@2722 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9