After changing user name for the files permissions it went well (it's actually not the name that is stored, but the user ID, which use to be a nubmer counting from 500 and up...)
now I got the libraries still in /usr/share.... but with myself as the only user that can change in it. (Nobody else will ever use kicad on this PC) Some day I will sort out which parts (in eeschema) and modules I have changed and place them all in my special library file. Thanks a lot, folks!
