Kconfig no longer outputs a .config with freshly updated defconfigs

[Josh Boyer <jwboyer@linux.vnet.ibm.com>]

I was going through the somewhat tedious task of updating the 4xx
defconfigs today, and I noticed some odd behavior from Kconfig.
Basically, I would do:

	make ppc44x_defconfig
	make oldconfig
	<build>
	cp .config arch/powerpc/configs/ppc44x_defconfig
	make distclean

I did this for a number of configs.  Then I went back and tried to build
ppc44x_defconfig again and I got this result:

[jwboyer@localhost linux-2.6]$ make ppc44x_defconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/basic/docproc
  HOSTCC  scripts/kconfig/conf.o
  HOSTCC  scripts/kconfig/kxgettext.o
  SHIPPED scripts/kconfig/zconf.tab.c
  SHIPPED scripts/kconfig/lex.zconf.c
  SHIPPED scripts/kconfig/zconf.hash.c
  HOSTCC  scripts/kconfig/zconf.tab.o
scripts/kconfig/lex.zconf.c:1628: warning: ‘input’ defined but not used
  HOSTLD  scripts/kconfig/conf
[jwboyer@localhost linux-2.6]$ make oldconfig
scripts/kconfig/conf -o arch/powerpc/Kconfig
#
# using defaults found in /boot/config-2.6.25.13-104.fc9.ppc64
#

There was no .config file present after the initial 'make
ppc44x_defconfig', so it defaulted to using something in /boot.  I'm a
bit baffled here, but that seems to be common to any newly updated
defconfig I've done.

Was there a change to Kconfig recently that won't copy the defconfig
file to .config if there are no symbol changes or something like that?

josh