x86: biarch support for 32 bit builds beautified

There were no reason to mess around with CC, AS and LD.
Fixing this up avoided duplicated option for ld.

A small fixlet were needed in boot/Makefile which assumed
that CC were modified.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/Makefile

@@ -15,18 +15,15 @@ export BITS
 ifeq ($(CONFIG_X86_32),y)
         BITS := 32
         UTS_MACHINE := i386
+        CHECKFLAGS += -D__i386__
 
-        HAS_BIARCH := $(call cc-option-yn, -m32)
-        ifeq ($(HAS_BIARCH),y)
-                AS := $(AS) --32
-                LD := $(LD) -m elf_i386
-                CC := $(CC) -m32
-        endif
+        biarch := $(call cc-option,-m32)
+        KBUILD_AFLAGS += $(biarch)
+        KBUILD_CFLAGS += $(biarch)
 
         ifdef CONFIG_RELOCATABLE
                 LDFLAGS_vmlinux := --emit-relocs
         endif
-        CHECKFLAGS += -D__i386__
 
         KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
 

arch/x86/boot/Makefile

@@ -49,10 +49,7 @@ HOSTCFLAGS_build.o := $(LINUXINCLUDE)
 
 # 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.
-cflags-$(CONFIG_X86_32) :=
-cflags-$(CONFIG_X86_64) := -m32
 KBUILD_CFLAGS	:= $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
-		   $(cflags-y) \
 		   -Wall -Wstrict-prototypes \
 		   -march=i386 -mregparm=3 \
 		   -include $(srctree)/$(src)/code16gcc.h \
@@ -62,6 +59,7 @@ KBUILD_CFLAGS	:= $(LINUXINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \
 			$(call cc-option, -fno-unit-at-a-time)) \
 		   $(call cc-option, -fno-stack-protector) \
 		   $(call cc-option, -mpreferred-stack-boundary=2)
+KBUILD_CFLAGS +=   $(call cc-option,-m32)
 KBUILD_AFLAGS	:= $(KBUILD_CFLAGS) -D__ASSEMBLY__
 
 $(obj)/zImage:  IMAGE_OFFSET := 0x1000