FreeBSD mount_null

[Valerio daelli]

Hello all
I would like to use freebsd mount_null features and I've tried
with some 2001 sources. But we didn't succedeed in installing it from sources
since it complaints about some functions missing:

mount_null.o(.text+0x10a): In function `main':
: undefined reference to `vfsisloadable'
mount_null.o(.text+0x11e): In function `main':
: undefined reference to `vfsload'
mount_null.o(.text+0x139): In function `main':
: undefined reference to `endvfsent'

Any help is really appreciated.
Bye

Valerio