Hi Collin, I have tried it, but it remains the same. I have also checked the folder /usr/lib/x86_64-linux-gnu/ and 1.6.6 is still there, no 1.6.8 version. Have I done something wrong?
edit: I see these builded files in the /usr/local/lib/ (not in /usr/lib/x86_64-linux-gnu/). So i have copied them to the correct folder ( /usr/lib/x86_64-linux-gnu/) and build once again. Unfortunately, there is no improvement.