4.9 buildworld fails

[admin2 at forkthepenguin.com]

Hello all,
	I have two (nearly) identical systems running REL_ENG_4_9, but one
fails to complete a buildworld (error below). The randomly named file
is gone when the error occurs, so I can't find out why the strip
operation is not permitted. Securelevel is -1 and this fails in single
user mode. I'm out of places to look, any ideas?

Chris

===> bin/cat
install -s -o root -g wheel -m 555   cat /bin
/usr/obj/usr/src/i386/usr/libexec/elf/strip: /bin/stVzpCWB: Operation not
permitted
install: wait: Operation not permitted
*** Error code 70

Stop in /usr/src/bin/cat.
*** Error code 1

Stop in /usr/src/bin.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.