Which results in a /tmp/pam-debug.log file being created and *readable* by everybody! Hope you'll remember to remove the DEBUG flag before releasing 6.2 :-) ... [At least that's the behavior I have on three different machines, whithout playing with anything]
Actually explained by a Debian bug report : http://www.chiark.greenend.org.uk/debian/Bugs/db/44/44684.html
Fixed in 0.72-3 and later.