[PATCH] kbuild: improve option checking, Kbuild.include cleanup

 GNU binutils, root users, tmpfiles, external modules ro builds must
 be fixed to do the right thing now.

Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Horst Schirmeier <horst@schirmeier.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Daniel Drake <dsd@gentoo.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Oleg Verych <olecom@flower.upol.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>