kbuild: announce removal of SUBDIRS if used
SUBDIRS has been kept as a backward compatibility since
commit ("[PATCH] kbuild: external module support") in 2002.
We do not need multiple ways to do the same thing, so I will remove
SUBDIRS after the Linux 5.3 release. I cleaned up in-tree code, and
updated the document so that nobody would try to use it.
Meanwhile, display the following warning if SUBDIRS is used.
Makefile:189: ================= WARNING ================
Makefile:190: 'SUBDIRS' will be removed after Linux 5.3
Makefile:191: Please use 'M=' or 'KBUILD_EXTMOD' instead
Makefile:192: ==========================================
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Boris Brezillon <boris.brezillon@bootlin.com> # for scx200_docflash.c
Acked-by: Guenter Roeck <linux@roeck-us.net> # for scx200_wdt.c
diff --git a/Makefile b/Makefile
index 96b4ea5..9fcd8f8 100644
--- a/Makefile
+++ b/Makefile
@@ -186,6 +186,10 @@
# Old syntax make ... SUBDIRS=$PWD is still supported
# Setting the environment variable KBUILD_EXTMOD take precedence
ifdef SUBDIRS
+ $(warning ================= WARNING ================)
+ $(warning 'SUBDIRS' will be removed after Linux 5.3)
+ $(warning Please use 'M=' or 'KBUILD_EXTMOD' instead)
+ $(warning ==========================================)
KBUILD_EXTMOD ?= $(SUBDIRS)
endif