minimal build fixes for uml (fallout from x86 merge)

 a) include/asm-um/arch can't just point to include/asm-$(SUBARCH) now
 b) arch/{i386,x86_64}/crypto are merged now
 c) subarch-obj needed changes
 d) cpufeature_64.h should pull "cpufeature_32.h", not <asm/cpufeature_32.h>
    since it can be included from asm-um/cpufeature.h
 e) in case of uml-i386 we need CONFIG_X86_32 for make and gcc, but not
    for Kconfig
 f) sysctl.c shouldn't do vdso_enabled for uml-i386 (actually, that one
    should be registered from corresponding arch/*/kernel/*, with ifdef
    going away; that's a separate patch, though).

With that and with Stephen's patch ("[PATCH net-2.6] uml: hard_header fix")
we have uml allmodconfig building both on i386 and amd64.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/Makefile-i386 b/arch/um/Makefile-i386
index c9f1c5b..60107ed 100644
--- a/arch/um/Makefile-i386
+++ b/arch/um/Makefile-i386
@@ -1,4 +1,4 @@
-core-y += arch/um/sys-i386/ arch/i386/crypto/
+core-y += arch/um/sys-i386/ arch/x86/crypto/
 
 TOP_ADDR := $(CONFIG_TOP_ADDR)
 
@@ -12,6 +12,7 @@
 ELF_ARCH		:= $(SUBARCH)
 ELF_FORMAT 		:= elf32-$(SUBARCH)
 OBJCOPYFLAGS  		:= -O binary -R .note -R .comment -S
+HEADER_ARCH		:= x86
 
 ifeq ("$(origin SUBARCH)", "command line")
 ifneq ("$(shell uname -m | sed -e s/i.86/i386/)", "$(SUBARCH)")
@@ -24,6 +25,11 @@
 endif
 endif
 
+CFLAGS			+= -DCONFIG_X86_32
+AFLAGS			+= -DCONFIG_X86_32
+CONFIG_X86_32		:= y
+export CONFIG_X86_32
+
 ARCH_KERNEL_DEFINES += -U__$(SUBARCH)__ -U$(SUBARCH)
 
 # First of all, tune CFLAGS for the specific CPU. This actually sets cflags-y.