chkrootkit's chklastlog is broken on gentoo (or specifically, any linux system that doesn't keep wtmp and lastlog in /var/adm), because the paths to wtmp and lastlog are hard-coded in chklastlog.c. ebuild patch attached. Cheers
Created attachment 35799 [details, diff] 01-chkrootkit-0.43-r3.diff
Fixed in CVS versions. chkrootkit-0.43-r1.ebuild chkrootkit-0.43-r2.ebuild chkrootkit-0.43.ebuild