kbuild: Allow to combine multiple W= levels

Add support for make W=12, make W=123 and so on, to enable warnings from
multiple W= levels. Normally, make W=<level> does not include warnings
from the previous level.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>

1 files changed, 1 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 4527dc23a724..d34250266f47 100644
--- a/Makefile
+++ b/Makefile
@@ -1290,7 +1290,7 @@ help:
         @echo  '                1: warnings which may be relevant and do not occur too often'
         @echo  '                2: warnings which occur quite often but may still be relevant'
         @echo  '                3: more obscure warnings, can most likely be ignored'
-
+        @echo  '                Multiple levels can be combined with W=12 or W=123'
         @echo  ''
         @echo  'Execute "make" or "make all" to build all targets marked with [*] '
         @echo  'For further info see the ./README file'