From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Mon, 5 Jan 2009 17:46:47 +0100
Subject: [PATCH 17/21] [klibc] use kernel header installed by "headers_install"

Originally klibc directly sets the compiler header search path
directly into the kernel tree. This causes compilation to fail on modern
kernel with a changed include dir layout.

This patch uses the "headers_install" to extract the includes from the
kernel. Against these headers klibc is build.

Ported from 1.5.15

Index: klibc-1.5.25/Makefile
===================================================================
--- klibc-1.5.25.orig/Makefile
+++ klibc-1.5.25/Makefile
@@ -6,6 +6,7 @@ SRCROOT = .
 # kbuild compatibility
 export srctree  := $(shell pwd)
 export objtree  := $(shell pwd)
+export LINUX_HEADERS := $(objtree)/linux-headers
 export KLIBCSRC := usr/klibc
 export VERSION := $(shell cat $(srctree)/$(KLIBCSRC)/version)
 export KLIBCINC := usr/include
@@ -102,16 +103,19 @@ $(KLIBCKERNELSRC):
 	@echo "KLIBCKERNELSRC=<path> to the build."
 	@false
 
+$(LINUX_HEADERS): linux
+	$(Q)$(MAKE) -C $(KLIBCKERNELSRC) ARCH=$(KLIBCARCH) INSTALL_HDR_PATH="$@" headers_install
+
 rpmbuild = $(shell which rpmbuild 2>/dev/null || which rpm)
 
 klibc.spec: klibc.spec.in $(KLIBCSRC)/version
 	sed -e 's/@@VERSION@@/$(VERSION)/g' < $< > $@
 
 # Build klcc - it is the first target
-klcc: $(objtree)/.config
+klcc: $(objtree)/.config  $(LINUX_HEADERS)
 	$(Q)$(MAKE) $(klibc)=klcc
 
-klibc: $(objtree)/.config
+klibc: $(objtree)/.config  $(LINUX_HEADERS)
 	$(Q)$(MAKE) $(klibc)=.
 
 test: klibc
Index: klibc-1.5.25/scripts/Kbuild.klibc
===================================================================
--- klibc-1.5.25.orig/scripts/Kbuild.klibc
+++ klibc-1.5.25/scripts/Kbuild.klibc
@@ -113,7 +113,7 @@ KLIBCCPPFLAGS    := -nostdinc -iwithpref
 # kernel include paths
 KLIBCKERNELSRC	 ?= $(srctree)
 KLIBCKERNELOBJ	 ?= $(objtree)
-KLIBCCPPFLAGS    += -I$(KLIBCKERNELSRC)/include				    \
+KLIBCCPPFLAGS    += -I$(LINUX_HEADERS)/include				    \
                      $(if $(KBUILD_SRC),-I$(KLIBCKERNELOBJ)/include2 	    \
 		       -I$(KLIBCKERNELOBJ)/include -I$(srctree)/include)    \
 		     $(KLIBCARCHINCFLAGS)