x86: enable "make ARCH=x86"

After unification of the Kconfig files and
introducing K64BIT support in kconfig
it required only trivial changes to enable
"make ARCH=x86".

With this patch you can build for x86_64 in several ways:
1) make ARCH=x86_64
2) make ARCH=x86 K64BIT=y
3) make ARCH=x86 menuconfig
   => select 64-bit

Likewise for i386 with the addition that
i386 is default is you say ARCH=x86.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>

Makefile

@@ -200,9 +200,11 @@ SRCARCH 	:= $(ARCH)
 # Additional ARCH settings for x86
 ifeq ($(ARCH),i386)
         SRCARCH := x86
+        K64BIT  := n
 endif
 ifeq ($(ARCH),x86_64)
         SRCARCH := x86
+        K64BIT  := y
 endif
 
 KCONFIG_CONFIG	?= .config
@@ -339,7 +341,7 @@ KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
 KERNELVERSION = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
 
 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
-export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
+export ARCH SRCARCH K64BIT CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL UTS_MACHINE
 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 

arch/x86/Kconfig

 # x86 configuration
+mainmenu "Linux Kernel Configuration for x86"
+
+# Select 32 or 64 bit
+config 64BIT
+	bool "64-bit kernel"
+	default n
+	help
+	  Say yes to build a 64-bit kernel - formerly known as x86_64
+	  Say no to build a 32-bit kernel - formerly known as i386
+
+config X86_32
+	def_bool !64BIT
+
+config X86_64
+	def_bool 64BIT
 
 ### Arch settings
 config X86
 	bool
 	default y
 
-config 64BIT
-	def_bool X86_64
-
 config GENERIC_TIME
 	bool
 	default y

arch/x86/Kconfig.i386

-#
-# For a description of the syntax of this configuration file,
-# see Documentation/kbuild/kconfig-language.txt.
-#
-
-mainmenu "Linux Kernel Configuration"
-
-config X86_32
-	bool
-	default y
-	help
-	  This is Linux's home port.  Linux was originally native to the Intel
-	  386, and runs on all the later x86 processors including the Intel
-	  486, 586, Pentiums, and various instruction-set-compatible chips by
-	  AMD, Cyrix, and others.
-
-
-source "arch/x86/Kconfig"

arch/x86/Kconfig.x86_64

-#
-# For a description of the syntax of this configuration file,
-# see Documentation/kbuild/kconfig-language.txt.
-#
-# Note: ISA is disabled and will hopefully never be enabled.
-# If you managed to buy an ISA x86-64 box you'll have to fix all the
-# ISA drivers you need yourself.
-#
-
-mainmenu "Linux Kernel Configuration"
-
-config X86_64
-	bool
-	default y
-	help
-	  Port to the x86-64 architecture. x86-64 is a 64-bit extension to the
-	  classical 32-bit x86 architecture. For details see
-	  <http://www.x86-64.org/>.
-
-source "arch/x86/Kconfig"

scripts/kconfig/Makefile

@@ -4,12 +4,7 @@
 
 PHONY += oldconfig xconfig gconfig menuconfig config silentoldconfig update-po-config
 
-# If a arch/$(SRCARCH)/Kconfig.$(ARCH) file exist use it
-ifneq ($(wildcard $(srctree)/arch/$(SRCARCH)/Kconfig.$(ARCH)),)
-        Kconfig := arch/$(SRCARCH)/Kconfig.$(ARCH)
-else
-        Kconfig := arch/$(SRCARCH)/Kconfig
-endif
+Kconfig := arch/$(SRCARCH)/Kconfig
 
 xconfig: $(obj)/qconf
 	$< $(Kconfig)