I'm trying to build an ISDN kernel using the iwic driver and therefore
it's 1.6P. The build fails in the link stage with:

making sure the compat library is up to date...
`libcompat.a' is up to date.
making sure the kern library is up to date...
`libkern.o' is up to date.
ld -T ../../../../arch/i386/conf/kern.ldscript -Ttext c0100000 -e start -X
-o netbsd ${SYSTEM_OBJ} ${EXTRA_OBJ} vers.o
i4b_ctl.o: In function `isdnctlioctl':
i4b_ctl.o(.text+0xdd): undefined reference to `i4b_l1_debug'
i4b_ctl.o(.text+0x103): undefined reference to `i4b_l1_debug'
iwic_pci.o: In function `iwic_mph_command_req':
iwic_pci.o(.text+0x3b2): undefined reference to `i4b_l1_debug'
iwic_pci.o(.text+0x3e6): undefined reference to `i4b_l1_debug'
iwic_pci.o(.text+0x416): undefined reference to `i4b_l1_debug'
iwic_pci.o(.text+0x456): more undefined references to `i4b_l1_debug'
follow
*** Error code 1

Stop.
make: stopped in /usr/src/sys/arch/i386/compile/TOTTY_ISDN

Without the ISDN stuff the kernel builds (and runs) fine.

Any ideas?

Torsten