RELENG_6: make world is broken at sys/modules/if_tap when MODULES_WITH_WORLD=yes

[Eugene Grosbein]

Hi!

make buildworld of RELENG_6 fails if /etc/make.conf
contains MODULES_WITH_WORLD=yes:

[skip lots of lines]

===> sys/modules/if_tap (depend)
@ -> /usr/local/src/sys
machine -> /usr/local/src/sys/i386/include
echo "#define INET 1" > opt_inet.h
awk -f @/tools/vnode_if.awk @/kern/vnode_if.src -p
awk -f @/tools/vnode_if.awk @/kern/vnode_if.src -q
awk -f @/tools/vnode_if.awk @/kern/vnode_if.src -h
rm -f .depend
mkdep -f .depend -a   -nostdinc -D_KERNEL -DKLD_MODULE -I- -I. -I@ -I@/contrib/altq -I@/../include -I/usr/obj/usr/local/src/tmp/usr/include /usr/local/src/sys/modules/if_tap/../../net/if_tap.c
/usr/local/src/sys/modules/if_tap/../../net/if_tap.c:38:24: opt_compat.h: No such file or directory
mkdep: compile failed
*** Error code 1

Stop in /usr/local/src/sys/modules/if_tap.
*** Error code 1

There was already very similar breakage:
http://freebsd.rambler.ru/bsdmail/freebsd-current_2005/msg07955.html

Please help.

Eugene Grosbein