Disable gl backend by default, just like autotools does:

  --enable-gl=[no/auto/yes]
                          Enable cairo's OpenGL surface backend feature
                          [default=no]
  --enable-glesv2=[no/auto/yes]
                          Enable cairo's OpenGLESv2 surface backend feature
                          [default=no]
  --enable-glesv3=[no/auto/yes]
                          Enable cairo's OpenGLESv3 surface backend feature
                          [default=no]