mount_nfs is broken

Someone appears to have broken mount_nfs.

I rebuilt kernel and world and install it on my primary
system.  Everything appears be working fine.  So, I then
update the first node in my cluster.  It reboots fine
until the node tries to mount the users' home directories.
The line in /etc/fstab is

node10:/home    /home    nfs   rw,noatime   0   0

Trying to manually mount /home, I find

% mount_nfs 192.168.0.10:/usr/home /home
mount_nfs: /usr/home, mount option <sec> is unknown: Invalid argument

There are no clues in src/UPDATING concerning incompatibilities
with NFS.

I do not use modules.  The kernels are identical on the
two system and it was built with 

options         NFSCLIENT               # Network Filesystem Client
options         NFSSERVER               # Network Filesystem Server
options         NFS_LEGACYRPC

The last option is only documented at

http://www.freebsd.org/cgi/cvsweb.cgi/src/sbin/mount_nfs/mount_nfs.c

The wonderfully fun part of this problem is that I can no longer
NFS mount /usr/src from the node.  

-- 
Steve