Ok, then it was probably an old version of libfreetype (not installed as ubuntu package) causing the problem. After removing all libfreetype files in /usr/local/lib, the symbolic link seized to appear at libfreetype6 or libxft re-installation. Thank you for your help, Sebastian! But, I'm curious, why did this symbolic link re-appear every time I re-installed some Ubuntu packages? Always nice to learn something from the problems you run into...
Ok, then it was probably an old version of libfreetype (not installed as ubuntu package) causing the problem. After removing all libfreetype files in /usr/local/lib, the symbolic link seized to appear at libfreetype6 or libxft re-installation. Thank you for your help, Sebastian! But, I'm curious, why did this symbolic link re-appear every time I re-installed some Ubuntu packages? Always nice to learn something from the problems you run into...