kern/48901: kernel doesn't build without INET6

[alnsn%NetBSD.org@localhost]

>Number:         48901
>Category:       kern
>Synopsis:       kernel doesn't build without INET6
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jun 12 11:10:00 +0000 2014
>Originator:     Alexander Nasonov
>Release:        NetBSD 6.99.43
>Organization:
NetBSD
>Environment:
System: NetBSD neva 6.99.43 NetBSD 6.99.43 (GENERIC) #0: Thu Jun 12 10:32:05 
BST 2014  
alnsn@neva:/home/alnsn/netbsd-current/src/sys/arch/amd64/compile/obj/GENERIC 
amd64
Architecture: x86_64
Machine: amd64
>Description:
        GENERIC kernel doesn't link if 'options INET6' is commented out:
        $ ./build.sh -U kernel=GENERIC
        ...
        #      link  GENERIC/netbsd
        /home/alnsn/netbsd-current/tooldir.gcc48.amd64/bin/x86_64--netbsd-ld 
-Map netbsd.map --cref -T 
/home/alnsn/netbsd-current/src/sys/arch/amd64/conf/kern.ldscript -Ttext 
0xffffffff80100000 -e start -z max-page-size=0x100000 -X -o netbsd 
${SYSTEM_OBJ} ${EXTRA_OBJ} vers.o
        if_stf.o: In function `in_stf_input':
        if_stf.c:(.text+0x4e8): undefined reference to `ip6_pktq'
        *** [netbsd] Error code 1

        nbmake: stopped in 
/home/alnsn/netbsd-current/src/sys/arch/amd64/compile/obj/GENERIC
        1 error

        nbmake: stopped in 
/home/alnsn/netbsd-current/src/sys/arch/amd64/compile/obj/GENERIC

        ERROR: Failed to make all in 
"/home/alnsn/netbsd-current/src/sys/arch/amd64/compile/obj/GENERIC"
        *** BUILD ABORTED ***
>How-To-Repeat:
        Comment out 'options INET6' from sys/arch/amd64/conf/GENERIC.
>Fix:
        I haven't tried fixing it.