randconfig build error with next-20140203, in fs/btrfs

Building with the attached random configuration file,

fs/built-in.o: In function `btrfs_csum_data':
/home/jim/linux/fs/btrfs/disk-io.c:247: undefined reference to `crc32c'
/home/jim/linux/fs/btrfs/disk-io.c:247: undefined reference to `crc32c'
/home/jim/linux/fs/btrfs/disk-io.c:247: undefined reference to `crc32c'
/home/jim/linux/fs/btrfs/disk-io.c:247: undefined reference to `crc32c'
fs/built-in.o: In function `send_cmd':
/home/jim/linux/fs/btrfs/send.c:623: undefined reference to `crc32c'
fs/built-in.o:/home/jim/linux/fs/btrfs/check-integrity.c:1826: more undefined re
ferences to `crc32c' follow
make: *** [vmlinux] Error 1