Clang error make buildworld

[Roman Divacky]

> clang -O2 -pipe -march=native -fomit-frame-pointer
> -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/src/libexec/atrun/../../usr.bin/at -I/usr/src/libexec/atrun
> -DLOGIN_CAP -DPAM -std=gnu99 -fstack-protector -Wsystem-headers -Wall
> -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign -c
> /usr/src/libexec/atrun/gloadavg.c
> clang -O2 -pipe -march=native -fomit-frame-pointer
> -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/src/libexec/atrun/../../usr.bin/at -I/usr/src/libexec/atrun
> -DLOGIN_CAP -DPAM -std=gnu99 -fstack-protector -Wsystem-headers -Wall
> -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign  -o atrun atrun.o
> gloadavg.o -lpam -lutil
> clang: warning: argument unused during compilation: '-std=gnu99'
> /usr/obj/usr/src/tmp/usr/lib/crt1.o: In function `_start':
> /usr/src/lib/csu/amd64/crt1.c:(.text+0x5d): undefined reference to `atexit'


Can you invoke this very same command (ie. linking) with -### and show me?
Does it work when you try to link the same .o files without specifying
-march=native ?