Those (-session ...) command-line arguments are supplied by X11, not by KDE or other desktop environments. As written in my first email, Linphone just needs to
ignore them. The alternative is to wait for them to be automatically stripped (by GTK+ in Linphone's case). Surely you don't need me to write a patch for such a simple code modification ...
If you want to know the details, you can view
this KDE session management tutorial. However, you shouldn't need to add any of the code fragments they've supplied. My PyQt applications simply delay reading the command-line arguments until after the session ones are stripped. I also added code which checks that no other instances of the applications are running (via "ps -ef | grep <app>").