[PATCH 1/8] kbuild: add include/uapi to path

[Ahmad Fatoum]

Import the necessary bits out of the Linux Makefile, so include/uapi
goes into the path. This allows importing Linux headers without changing
the includes too much. Like with Linux <linux/*.h> is first searched
in include/, then include/uapi. Code that explicitly needs the uapi
header can include <uapi/linux/*.h>.

Signed-off-by: Ahmad Fatoum <ahmad at a3f.at>
---
 Makefile | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index f3c85cff9430..67efcc11f2e1 100644
--- a/Makefile
+++ b/Makefile
@@ -408,13 +408,21 @@ LDFLAGS_MODULE  = -T common/module.lds
 # even be read-only.
 export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
 
+# Use USERINCLUDE when you must reference the UAPI directories only.
+USERINCLUDE    := \
+		-I$(srctree)/arch/$(SRCARCH)/include/uapi \
+		-I$(objtree)/arch/$(SRCARCH)/include/generated/uapi \
+		-I$(srctree)/include/uapi \
+		-I$(objtree)/include/generated/uapi \
+                -include $(srctree)/include/linux/kconfig.h
+
 # Use LINUXINCLUDE when you must reference the include/ directory.
 # Needed to be compatible with the O= option
 LINUXINCLUDE    := -Iinclude -I$(srctree)/dts/include \
                    $(if $(building_out_of_srctree), -I$(srctree)/include) \
 		   -I$(srctree)/arch/$(SRCARCH)/include \
 		   -I$(objtree)/arch/$(SRCARCH)/include \
-                   -include $(srctree)/include/linux/kconfig.h
+		   $(USERINCLUDE)
 
 KBUILD_CPPFLAGS        := -D__KERNEL__ -D__BAREBOX__ $(LINUXINCLUDE) -fno-builtin -ffreestanding
 
-- 
2.30.0