[PATCH] kbuild: make clean rule robust against too long argument error

[Masahiro Yamada <masahiroy@kernel.org>]

Commit cd968b97c492 ("kbuild: make built-in.a rule robust against too
long argument error") made a build rule robust against "Argument list
too long" error.

Eugeniu Rosca reported the same error occurred when cleaning an external
module.

The $(obj)/ prefix can be a very long path for external modules.

Apply a similar solution to 'make clean'.

Reported-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 scripts/Makefile.clean | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean
index 3649900696dd..235408a44f90 100644
--- a/scripts/Makefile.clean
+++ b/scripts/Makefile.clean
@@ -37,8 +37,9 @@ __clean-files   := $(wildcard $(addprefix $(obj)/, $(__clean-files)))
 
 # ==========================================================================
 
+# Use xargs to make this robust against "Argument list too long" error
 quiet_cmd_clean = CLEAN   $(obj)
-      cmd_clean = rm -rf $(__clean-files)
+      cmd_clean = printf '$(obj)/%s ' $(patsubst $(obj)/%,%,$(__clean-files)) | xargs rm -rf
 
 __clean: $(subdir-ymn)
 ifneq ($(strip $(__clean-files)),)
-- 
2.39.2