kbuild: reintroduce ALLSOURCE_ARCHS support for tags/cscope

This patch reintroduce the ALLSOURCE_ARCHS support for tags/TAGS/
cscope targets. The Kbuild previously has this feature, but after
moving the targets into scripts/tags.sh, ALLSOURCE_ARCHS disappears.

It's something like this:

	$ make ALLSOURCE_ARCHS="x86 mips arm" tags cscope

Signed-off-by: Jike Song <albcamus@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
index 51771847e816..923f9ddee8f6 100644
--- a/Documentation/kbuild/kbuild.txt
+++ b/Documentation/kbuild/kbuild.txt
@@ -124,3 +124,10 @@ KBUILD_EXTRA_SYMBOLS
 --------------------------------------------------
 For modules use symbols from another modules.
 See more details in modules.txt.
+
+ALLSOURCE_ARCHS
+--------------------------------------------------
+For tags/TAGS/cscope targets, you can specify more than one archs
+to be included in the databases, separated by blankspace. e.g.
+
+    $ make ALLSOURCE_ARCHS="x86 mips arm" tags