GNU emacs locks files modified with CVS

[Pepijn Kenter <kenter_remove_spam@tpd.tno.nl>]

Hi all.

I've got a problem when I use su to log in as another user and try to 
edit a file that is modified in CVS. Let me show you the sequence of 
commands that leads to the problem.

When loged in as user1 type:
su user2
emacs file.pro # edit, exit and save the changes
emacs file.pro # file.pro is now read only.

I can not edit file.pro the second time because it is apperently locked 
by user2 (as shown in the status line? of emacs). File permissions are 
correct and the onwner of file.pro (still) is user2.

After some googling I think the possible cause is that emacs is 
inconsistent in the way it handles the USER and LOGNAME variables.
Indeed USER is set to user2 whereas LOGNAME is still user1. When I 
change LOGNAME to user2 the problem disappears.

So, what to do?
I've found a very old message (1994) with a patch to solve this problem
http://groups.google.nl/groups?q=LOGNAME+USER+emacs&hl=nl&lr=lang_de|lang_en|lang_nl&ie=UTF-8&oe=UTF-8&selm=9402100649.AA13033%40spot.twinsun.com&rnum=1
but I would expect that after all most 10 years the problem had been fixed.

A simpler solution would be to set the LOGNAME variable to user2 
somewhere. I've understood that the differences are mainly historical.
This seems to me an ugly work arround that may leed to problems 
elsewhere, so I prefer a more elegant solution.

Any help would be appriciated.
Pepijn Kenter.