Makefile: move KERNEL_ARCH from kernel-headers to here

Closes #2707

It's not only for kernel headers, and the kernel headers .mk file
isn't included for crosstool-ng toolchain, which broke linux/u-boot/..
builds.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

CHANGES

@@ -68,6 +68,7 @@
 	#2521: Can't compile sdl_mixer, mikmod.h can't be found
 	#2563: [PATCH] cairo: Expose the configure option to disable some...
 	#2581: libmms: Update to 0.6, and patch to work on architectures...
+	#2707: Can't compile linux kernel using buildroot + crosstool-ng
 
 2010.08: Released August 31th, 2010:
 

Makefile

@@ -249,6 +249,14 @@ ifeq ($(ARCH),xtensa)
 ARCH:=$(ARCH)_$(call qstrip,$(BR2_xtensa_core_name))
 endif
 
+KERNEL_ARCH:=$(shell echo "$(ARCH)" | sed -e "s/-.*//" \
+	-e s/i.86/i386/ -e s/sun4u/sparc64/ \
+	-e s/arm.*/arm/ -e s/sa110/arm/ \
+	-e s/parisc64/parisc/ \
+	-e s/powerpc64/powerpc/ \
+	-e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
+	-e s/sh.*/sh/)
+
 ZCAT:=$(call qstrip,$(BR2_ZCAT))
 BZCAT:=$(call qstrip,$(BR2_BZCAT))
 TAR_OPTIONS=$(call qstrip,$(BR2_TAR_OPTIONS)) -xf

toolchain/kernel-headers/kernel-headers.mk

@@ -13,14 +13,6 @@ LINUX_HEADERS_SITE:=127.0.0.1
 LINUX_HEADERS_SOURCE:=unspecified-kernel-headers
 LINUX_HEADERS_UNPACK_DIR:=$(TOOLCHAIN_DIR)/linux-libc-headers-null
 
-KERNEL_ARCH:=$(shell $(SHELL) -c "echo \"$(ARCH)\" | sed -e \"s/-.*//\" \
-	-e s/i.86/i386/ -e s/sun4u/sparc64/ \
-	-e s/arm.*/arm/ -e s/sa110/arm/ \
-	-e s/parisc64/parisc/ \
-	-e s/powerpc64/powerpc/ \
-	-e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
-	-e s/sh.*/sh/")
-
 include toolchain/kernel-headers/kernel-headers-new.makefile
 
 $(DL_DIR)/$(LINUX_HEADERS_SOURCE):