[PATCH v2 3/3] kernel-arch: add KERNEL_TOOLCHAIN to switch the whole kernel toolchain

[mark.yang@lge.com]

From: "mark.yang" <mark.yang@lge.com>

Setting TOOLCHAIN on the kernel recipe alone leaves modules and
make-mod-scripts running make against the shared build tree with gcc;
kbuild spots the CC_VERSION_TEXT mismatch and silently regenerates
the shared .config. Add a KERNEL_TOOLCHAIN switch covering all
kernel-arch recipes so they change toolchain together, gcc by default.

Signed-off-by: mark.yang <mark.yang@lge.com>
---
v2: rebased on the merged clang toolchain support which supersedes
    the other v1 patches; dependency changes split out into patch 2

 meta/classes-recipe/kernel-arch.bbclass | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/meta/classes-recipe/kernel-arch.bbclass b/meta/classes-recipe/kernel-arch.bbclass
index 321c9ed577..5f8dbacc0c 100644
--- a/meta/classes-recipe/kernel-arch.bbclass
+++ b/meta/classes-recipe/kernel-arch.bbclass
@@ -92,4 +92,5 @@ KERNEL_LD:toolchain-clang = "${@bb.utils.contains('DISTRO_FEATURES', 'ld-is-lld'
 KERNEL_AR:toolchain-clang = "llvm-ar ${HOST_AR_KERNEL_ARCH}"
 KERNEL_OBJCOPY:toolchain-clang = "llvm-objcopy ${HOST_OBJCOPY_KERNEL_ARCH}"
 KERNEL_STRIP:toolchain-clang = "llvm-strip"
-TOOLCHAIN = "gcc"
+KERNEL_TOOLCHAIN ?= "gcc"
+TOOLCHAIN = "${KERNEL_TOOLCHAIN}"