UAPI: Partition the header include path sets and add uapi/ header directories

Partition the header include path flags into two sets, one for kernelspace
builds and one for userspace builds.

Add the following directories to build after the ordinary include directories
so that #include will pick up the UAPI header directly if the kernel header
has been moved there.

The userspace set (represented by the USERINCLUDE make variable) contains:

	-I $(srctree)/arch/$(hdr-arch)/include/uapi
	-I arch/$(hdr-arch)/include/generated/uapi
	-I $(srctree)/include/uapi
	-I include/generated/uapi
	-include $(srctree)/include/linux/kconfig.h

and the kernelspace set (represented by the LINUXINCLUDE make variable)
contains:

	-I $(srctree)/arch/$(hdr-arch)/include
	-I arch/$(hdr-arch)/include/generated
	-I $(srctree)/include
	-I include		--- if not building in the source tree

plus everything in the USERINCLUDE set.

Then use USERINCLUDE in building the x86 boot code.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index f7535be..ce03476 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -37,7 +37,7 @@
 targets		+= $(setup-y)
 hostprogs-y	:= mkcpustr tools/build
 
-HOST_EXTRACFLAGS += -I$(srctree)/tools/include $(LINUXINCLUDE) \
+HOST_EXTRACFLAGS += -I$(srctree)/tools/include $(USERINCLUDE) \
 	            -D__EXPORTED_HEADERS__
 
 $(obj)/cpu.o: $(obj)/cpustr.h
@@ -52,7 +52,7 @@
 
 # How to compile the 16-bit code.  Note we always compile for -march=i386,
 # that way we can complain to the user if the CPU is insufficient.
-KBUILD_CFLAGS	:= $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
+KBUILD_CFLAGS	:= $(USERINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
 		   -DDISABLE_BRANCH_PROFILING \
 		   -Wall -Wstrict-prototypes \
 		   -march=i386 -mregparm=3 \
diff --git a/arch/x86/boot/mkcpustr.c b/arch/x86/boot/mkcpustr.c
index 919257f..4579eff 100644
--- a/arch/x86/boot/mkcpustr.c
+++ b/arch/x86/boot/mkcpustr.c
@@ -15,6 +15,8 @@
 
 #include <stdio.h>
 
+#include "../include/asm/required-features.h"
+#include "../include/asm/cpufeature.h"
 #include "../kernel/cpu/capflags.c"
 
 int main(void)