RELENG_5: zs(4) does not link without sbus

[Joerg Wunsch]

When trying to configure a kernel that has "device zs" but no
"device sbus", linking fails:

linking kernel
zs.o(.text+0x4a4): In function `zstty_attach':
: undefined reference to `zstty_console'
zs.o(.text+0x1064): In function `zstty_param':
: undefined reference to `zstty_set_speed'
*** Error code 1

Is zs supposed to depend on sbus?  There's no man page for it, so I
can't tell.

-- 
J"org Wunsch                                           Unix support engineer
joerg_wunsch at interface-systems.de        http://www.interface-systems.de/~j/