[PATCH 4.9 086/101] kbuild: clear LDFLAGS in the top Makefile

[Greg Kroah-Hartman]

From: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>

commit ce99d0bf312daf0178e640da9e3c93b773a67e7d upstream.

Currently LDFLAGS is not cleared, so same flags are accumulated in
LDFLAGS when the top Makefile is recursively invoked.

I found unneeded rebuild for ARCH=arm64 when CONFIG_TRIM_UNUSED_KSYMS
is enabled.  If include/generated/autoksyms.h is updated, the top
Makefile is recursively invoked, then arch/arm64/Makefile adds one
more '-maarch64linux'.  Due to the command line change, modules are
rebuilt needlessly.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Acked-by: Nicolas Pitre <nico@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 Makefile |    1 +
 1 file changed, 1 insertion(+)

--- a/Makefile
+++ b/Makefile
@@ -395,6 +395,7 @@ KBUILD_CFLAGS_KERNEL :=
 KBUILD_AFLAGS_MODULE  := -DMODULE
 KBUILD_CFLAGS_MODULE  := -DMODULE
 KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
+LDFLAGS :=
 GCC_PLUGINS_CFLAGS :=
 CLANG_FLAGS :=