Build error on CURRENT

I'm getting a compile error during buildworld here:



===> libexec/atrun (all)
cc -g  -DATJOB_DIR=\"/var/at/jobs/\"
-DLFILE=\"/var/at/jobs/.lockfile\"  -DLOADAVG_MX=1.5
-DATSPOOL_DIR=\"/var/at/spool\"  -DVERSION=\"2.9\" -DDAEMON_UID=1
-DDAEMON_GID=1  -DDEFAULT_BATCH_QUEUE=\'E\'  -DDEFAULT_AT_QUEUE=\'c\'
-DPERM_PATH=\"/var/at/\"
-I/usr/data/sb/head/libexec/atrun/../../usr.bin/at
-I/usr/data/sb/head/libexec/atrun -DLOGIN_CAP -DPAM -std=gnu99
-fstack-protector -Wsystem-headers -Werror -Wall -Wno-format-y2k
-Wno-uninitialized -Wno-pointer-sign -c
/usr/data/sb/head/libexec/atrun/atrun.c
${CTFCONVERT_CMD} expands to empty string
cc -g  -DATJOB_DIR=\"/var/at/jobs/\"
-DLFILE=\"/var/at/jobs/.lockfile\"  -DLOADAVG_MX=1.5
-DATSPOOL_DIR=\"/var/at/spool\"  -DVERSION=\"2.9\" -DDAEMON_UID=1
-DDAEMON_GID=1  -DDEFAULT_BATCH_QUEUE=\'E\'  -DDEFAULT_AT_QUEUE=\'c\'
-DPERM_PATH=\"/var/at/\"
-I/usr/data/sb/head/libexec/atrun/../../usr.bin/at
-I/usr/data/sb/head/libexec/atrun -DLOGIN_CAP -DPAM -std=gnu99
-fstack-protector -Wsystem-headers -Werror -Wall -Wno-format-y2k
-Wno-uninitialized -Wno-pointer-sign -c
/usr/data/sb/head/libexec/atrun/gloadavg.c
${CTFCONVERT_CMD} expands to empty string
cc -g  -DATJOB_DIR=\"/var/at/jobs/\"
-DLFILE=\"/var/at/jobs/.lockfile\"  -DLOADAVG_MX=1.5
-DATSPOOL_DIR=\"/var/at/spool\"  -DVERSION=\"2.9\" -DDAEMON_UID=1
-DDAEMON_GID=1  -DDEFAULT_BATCH_QUEUE=\'E\'  -DDEFAULT_AT_QUEUE=\'c\'
-DPERM_PATH=\"/var/at/\"
-I/usr/data/sb/head/libexec/atrun/../../usr.bin/at
-I/usr/data/sb/head/libexec/atrun -DLOGIN_CAP -DPAM -std=gnu99
-fstack-protector -Wsystem-headers -Werror -Wall -Wno-format-y2k
-Wno-uninitialized -Wno-pointer-sign  -o atrun atrun.o gloadavg.o
-lpam -lutil
/usr/obj/usr/data/sb/head/tmp/usr/lib/libc.so: undefined reference to `log'
*** [atrun] Error code 1

Stop in /usr/data/sb/head/libexec/atrun.
*** [all] Error code 1

Stop in /usr/data/sb/head/libexec.
*** [libexec.all__D] Error code 1

Stop in /usr/data/sb/head.
*** [everything] Error code 1

Stop in /usr/data/sb/head.
*** [buildworld] Error code 1


At first I thought maybe it was because of an old install (CURRENT as
of December 2011) so I built and installed stable/9.  That went off
just fine.

I thought it may be because my svn checkout of CURRENT got
interrupted, so I re-extracted from scratch and see the same thing.

I've also tried completely removing /usr/obj.  I've build with no -j flag.

Looking at the sources I don't see the symbol "log" in libc anywhere
except as a DEBUG local variable that is only used in one file, always
under DEBUG.  The only thing I see that's of interested is the
libexec.all__D target which I haven't yet grepped for to see what it
is.

My make.conf and src.conf are pretty sparse:

root_at_:/data/sb/head # cat /etc/make.conf
#LIBC_EXTRAMK=/usr/data/sb/ino64/tools/tools/shlib-compat/Makefile.sysfake
CFLAGS=-g

# added by use.perl 2011-09-17 07:04:17
PERL_VERSION=5.12.4

root_at_:/data/sb/head # cat /etc/src.conf
#WITHOUT_CLANG=yes

Clearly the tinderbox machines aren't hitting this, and I didn't see
anything in the mailing list either.  So it's almost certainly
something on my end, but I'm at a loss as to what it could be.

Thanks,
matthew