Problem building NetBSD 3.1 with MKSENDMAIL=no

Hi,

I did a "./build.sh -U distribution" on my source tree, which is the
NetBSD 3.1 branch. It fails with

[...]

cd /usr/src/distrib/sets &&  DESTDIR=/usr/src/destdir.i386  MACHINE=i386 MACHINE
_ARCH=i386  CKSUM=/usr/src/tooldir.NetBSD-3.0.2_PATCH-i386/bin/nbcksum MAKE=/usr
/src/tooldir.NetBSD-3.0.2_PATCH-i386/bin/nbmake MTREE=/usr/src/tooldir.NetBSD-3.
0.2_PATCH-i386/bin/nbmtree  MKTEMP=/usr/src/tooldir.NetBSD-3.0.2_PATCH-i386/bin/
nbmktemp PAX=/usr/src/tooldir.NetBSD-3.0.2_PATCH-i386/bin/nbpax HOST_SH=sh  sh .
/checkflist    -M /usr/src/destdir.i386/METALOG

============  4 extra files  ===============
Files in DESTDIR but missing from flist.
File is obsolete or flist is out of date ?
------------------------------------------
./usr/share/man/cat1/mailq.0
./usr/share/man/cat1/newaliases.0
./usr/share/man/man1/mailq.1
./usr/share/man/man1/newaliases.1
=========  end of 4 extra files  ===========

[...]

I have MKSENDMAIL=no in /etc/mk.conf. Any ideas what I'm doing wrong?

Best,
--Lorenz