This fix is a kludge:
- make the nfs filehandle conditional on v2 and v3
- set the nfs_args fields for the version and the
file handle size.
- make the file handle pointer type void * so that
it works on both nfsv2 and nfsv3
- fix the mountd rpc results parsing.
A proper fix should:
- register an nfsv3 server for amd.
- make amd try v2/v3 mounts exactly like mount_nfs does.
- understand the nfsv3 mount options.
- cleanup the #undef's in the protocol header.
Also in order to auto-recognize v2 vs v3, I moved the inclusion of
<sys/mount.h> to am.h.
