buildworld fails as non-root user

Hi,

I can't buildworld as a regular user with a clean /usr/obj:

building static egacy library
ranlib libegacy.a
install -C -C -o root -g wheel -m 444   libegacy.a /usr/obj/usr/src/i386/legacy/usr/lib
install: /usr/obj/usr/src/i386/legacy/usr/lib/libegacy.a: chown/chgrp: Operation not permitted
*** Error code 71
 
Stop in /usr/src/tools/build.
*** Error code 1
 
Stop in /usr/src.
*** Error code 1
 
Stop in /usr/src.
*** Error code 1
 
Stop in /usr/src.

Before Stage 1.1 I also see a bunch of 'Operation not permitted' errors:

mtree -deU -f /usr/src/etc/mtree/BSD.include.dist  -p /usr/obj/usr/src/i386/usr/include
. changed
        user expected 0 found 1000 not modified: Operation not permitted
        permissions expected 0755 found 0700 modified
./arpa missing (created)
./arpa: user/group/mode not modified: Operation not permitted
./arpa: warning: file mode not set
./bsnmp missing (created)
./bsnmp: user/group/mode not modified: Operation not permitted
./bsnmp: warning: file mode not set
./c++ missing (created)
./c++/3.3 missing (created)
./c++/3.3/backward missing (created)
./c++/3.3/backward: user/group/mode not modified: Operation not permitted
./c++/3.3/backward: warning: file mode not set
[...]
./sys missing (created)
./sys: user/group/mode not modified: Operation not permitted
./sys: warning: file mode not set
./ufs missing (created)
./ufs/ffs missing (created)
./ufs/ffs: user/group/mode not modified: Operation not permitted
./ufs/ffs: warning: file mode not set
./ufs/ufs missing (created)
./ufs/ufs: user/group/mode not modified: Operation not permitted
./ufs/ufs: warning: file mode not set
./ufs: user/group/mode not modified: Operation not permitted
./ufs: warning: file mode not set
./vm missing (created)
./vm: user/group/mode not modified: Operation not permitted
./vm: warning: file mode not set
ln -sf /usr/src/sys /usr/obj/usr/src/i386

Is this expected behaviour? Is there a workaround?

tks
-- 
pica