[next] kbuild: use $(srctree) instead of KBUILD_SRC to check out-of-tree build

[Sergey Senozhatsky]

Hello Masahiro,

It seems that commit a9a49c2ad9b9b8 (linux-next) breaks ./scripts/tags.sh
on my system. It scans, basically, my entire drive now (including the
root partition):

$ ./scripts/tags.sh tags
find: â/arch/*.[chS]/â: No such file or directory
find: â/includeâ: No such file or directory
find: â/boot/lost+foundâ: Permission denied
find: â/etc/pacman.d/gnupg/openpgp-revocs.dâ: Permission denied
find: â/etc/pacman.d/gnupg/private-keys-v1.dâ: Permission denied
find: â/etc/pacman.d/gnupg/crls.dâ: Permission denied
find: â/etc/polkit-1/rules.dâ: Permission denied
find: â/etc/sudoers.dâ: Permission denied
find: â/etc/audisp/plugins.dâ: Permission denied
find: â/home/lost+foundâ: Permission denied
find: â/home/skâ: Permission denied
find: â/lost+foundâ: Permission denied
ctags: Warning: --extra option is obsolete; use --extras instead
[..]


With reverted a9a49c2ad9b9b8 tags scans kernel source tree only

./scripts/tags.sh tags
find: âarch/*.[chS]/â: No such file or directory
ctags: Warning: --extra option is obsolete; use --extras instead
[..]

	-ss