um: merge Makefile-{i386,x86_64}

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/Makefile

@@ -20,8 +20,18 @@ core-y			+= $(ARCH_DIR)/kernel/		\
 
 MODE_INCLUDE	+= -I$(srctree)/$(ARCH_DIR)/include/shared/skas
 
+HEADER_ARCH 	:= $(SUBARCH)
+
+# Additional ARCH settings for x86
+ifeq ($(SUBARCH),i386)
+        HEADER_ARCH := x86
+endif
+ifeq ($(SUBARCH),x86_64)
+        HEADER_ARCH := x86
+endif
+
 include $(srctree)/$(ARCH_DIR)/Makefile-skas
-include $(srctree)/$(ARCH_DIR)/Makefile-$(SUBARCH)
+include $(srctree)/$(ARCH_DIR)/Makefile-$(HEADER_ARCH)
 
 SHARED_HEADERS	:= $(ARCH_DIR)/include/shared
 ARCH_INCLUDE	:= -I$(srctree)/$(SHARED_HEADERS)

arch/um/Makefile-i386 → arch/um/Makefile-x86

@@ -1,11 +1,11 @@
 core-y += arch/um/sys-x86/ arch/x86/crypto/
 
+ifeq ($(CONFIG_X86_32),y)
 START := 0x8048000
 
 LDFLAGS			+= -m elf_i386
 ELF_ARCH		:= i386
 ELF_FORMAT 		:= elf32-i386
-HEADER_ARCH		:= x86
 CHECKFLAGS	+= -D__i386__
 
 ifeq ("$(origin SUBARCH)", "command line")
@@ -36,3 +36,26 @@ KBUILD_CFLAGS += $(shell if [ $(call cc-version) -lt 0400 ] ; then \
 			else echo $(call cc-option,-funit-at-a-time); fi ;)
 
 KBUILD_CFLAGS += $(cflags-y)
+
+else
+
+START := 0x60000000
+
+KBUILD_CFLAGS += -fno-builtin -m64 
+
+CHECKFLAGS  += -m64 -D__x86_64__
+KBUILD_AFLAGS += -m64
+LDFLAGS += -m elf_x86_64
+KBUILD_CPPFLAGS += -m64
+
+ELF_ARCH := i386:x86-64
+ELF_FORMAT := elf64-x86-64
+
+# Not on all 64-bit distros /lib is a symlink to /lib64. PLD is an example.
+
+LINK-$(CONFIG_LD_SCRIPT_DYN) += -Wl,-rpath,/lib64
+LINK-y += -m64
+
+# Do unit-at-a-time unconditionally on x86_64, following the host
+KBUILD_CFLAGS += $(call cc-option,-funit-at-a-time)
+endif