[PATCH] Makefile: add KCFLAGS to build with Yocto SDK

[Vincent Davis Jr <vince@underview.tech>]

When running

make -C \
"${SDKTARGETSYSROOT}/lib/modules/<kernel version>/build" \
modules_prepare

Issue that are encountered include

make -f ./Makefile syncconfig
make -f ./scripts/Makefile.build obj=scripts/basic
   92 | #include <sys/types.h>
      |          ^~~~~~~~~~~~~
compilation terminated.

ld: cannot find Scrt1.o: No such file or directory
ld: cannot find crti.o: No such file or directory
ld: cannot find crtbeginS.o: No such file or directory
ld: cannot find -lgcc: No such file or directory
ld: cannot find -lgcc_s: No such file or directory
ld: cannot find -lc: No such file or directory
ld: cannot find -lgcc: No such file or directory
ld: cannot find -lgcc_s: No such file or directory
ld: cannot find crtendS.o: No such file or directory
ld: cannot find crtn.o: No such file or directory

Solved by setting KCFLAGS as the yocto project SDK
KCFLAGS is set to --sysroot="${SDKTARGETSYSROOT}".

Signed-off-by: Vincent Davis Jr <vince@underview.tech>
---
 Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 64c514f4bc19..bbe7b0503841 100644
--- a/Makefile
+++ b/Makefile
@@ -459,7 +459,7 @@ HOSTRUSTC = rustc
 HOSTPKG_CONFIG	= pkg-config
 
 KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
-			 -O2 -fomit-frame-pointer -std=gnu11
+			 -O2 -fomit-frame-pointer -std=gnu11 $(KCFLAGS)
 KBUILD_USERCFLAGS  := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS)
 KBUILD_USERLDFLAGS := $(USERLDFLAGS)
 
@@ -491,7 +491,7 @@ KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS) \
 		       -I $(srctree)/scripts/include
 KBUILD_HOSTRUSTFLAGS := $(rust_common_flags) -O -Cstrip=debuginfo \
 			-Zallow-features= $(HOSTRUSTFLAGS)
-KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
+KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS) $(KCFLAGS)
 KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
 KBUILD_PROCMACROLDFLAGS := $(or $(PROCMACROLDFLAGS),$(KBUILD_HOSTLDFLAGS))
 
-- 
2.43.0