[RELENG_4] buildkernel failure with MAKEOBJDIRPREFIX

[NAKAJI Hiroyuki]

Hello,

I tried to rebuild a debug kernel to analyze one of my problem(*),
and, I faced to another problem. Now this is the main problem for me.

The problem I have now is that 'make buildkernel' does not refer to
${MAKEOBJDIRPREFIX} set in /etc/make.conf. The reason I will use
MAKEOBJDIRPREFIX is that my /usr/obj does not have enough space to
build the debug kernel with DEBUG=-g.

I set MAKEOBJDIRPREFIX=/other/big/directory in /etc/make.conf and ran
'make buildkernel' in /usr/src. And got an error "/usr/src: file
system full". Because /usr/src is another partition and has as small
space as /usr/obj. /usr/src is 400MB and /usr/obj is 500MB which are
enouch to build normal RELENG_4 world.

I noticed that modules are built in /usr/src/sys/modules not in
${MAKEOBJDIRPREFIX}/usr/src/sys/modules. Of cource, kernel.debug is
created in ${MAKEOBJDIRPREFIX}/usr/src/sys/CONFIG/kernel.debug.

I think this is a bug of make, *.mk or other Makefiles in /sys but I
cannot fix it.

(*) When running /usr/sbin/ppp to connect to the provider with PPPoE,
the system gets panic with 'fatal trap 12' after several days of
uptime. I have seen this panic twice in these 10 days.
-- 
NAKAJI Hiroyuki