[PATCH] uml: tidy biarch gcc support

On top of the previous biarch changes for UML, this makes the preprocessor
changes a bit cleaner.  Specify the 64-bit build in CPPFLAGS on the x86_64
SUBARCH, rather than #undef'ing i386.  Compile-tested with i386 and x86_64
SUBARCHs.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/Makefile-x86_64

@@ -11,6 +11,7 @@ USER_CFLAGS += -fno-builtin -m64
 CHECKFLAGS  += -m64
 AFLAGS += -m64
 LDFLAGS += -m elf_x86_64
+CPPFLAGS += -m64
 
 ELF_ARCH := i386:x86-64
 ELF_FORMAT := elf64-x86-64

arch/um/kernel/vmlinux.lds.S

-/* in case the preprocessor is a 32bit one */
-#undef i386
 #ifdef CONFIG_LD_SCRIPT_STATIC
 #include "uml.lds.S"
 #else