--- zzzz-none-000/linux-3.10.107/arch/um/Makefile	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/um/Makefile	2021-02-04 17:41:59.000000000 +0000
@@ -6,6 +6,17 @@
 # Licensed under the GPL
 #
 
+# select defconfig based on actual architecture
+ifeq ($(SUBARCH),x86)
+  ifeq ($(shell uname -m),x86_64)
+        KBUILD_DEFCONFIG := x86_64_defconfig
+  else
+        KBUILD_DEFCONFIG := i386_defconfig
+  endif
+else
+        KBUILD_DEFCONFIG := $(SUBARCH)_defconfig
+endif
+
 ARCH_DIR := arch/um
 OS := $(shell uname -s)
 # We require bash because the vmlinux link and loader script cpp use bash
@@ -22,19 +33,18 @@
 
 HEADER_ARCH 	:= $(SUBARCH)
 
-# Additional ARCH settings for x86
-ifeq ($(SUBARCH),i386)
-        HEADER_ARCH := x86
+ifneq ($(filter $(SUBARCH),x86 x86_64 i386),)
+	HEADER_ARCH := x86
 endif
-ifeq ($(SUBARCH),x86_64)
-        HEADER_ARCH := x86
+
+ifdef CONFIG_64BIT
 	KBUILD_CFLAGS += -mcmodel=large
 endif
 
 HOST_DIR := arch/$(HEADER_ARCH)
 
-include $(srctree)/$(ARCH_DIR)/Makefile-skas
-include $(srctree)/$(HOST_DIR)/Makefile.um
+include $(ARCH_DIR)/Makefile-skas
+include $(HOST_DIR)/Makefile.um
 
 core-y += $(HOST_DIR)/um/
 
@@ -58,12 +68,13 @@
 
 KBUILD_AFLAGS += $(ARCH_INCLUDE)
 
-USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -D__KERNEL__,,\
-	$(patsubst -I%,,$(KBUILD_CFLAGS)))) $(ARCH_INCLUDE) $(MODE_INCLUDE) \
-	$(filter -I%,$(CFLAGS)) -D_FILE_OFFSET_BITS=64 -idirafter include
+USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \
+		$(ARCH_INCLUDE) $(MODE_INCLUDE) $(filter -I%,$(CFLAGS)) \
+		-D_FILE_OFFSET_BITS=64 -idirafter $(srctree)/include \
+		-idirafter $(obj)/include -D__KERNEL__ -D__UM_HOST__
 
 #This will adjust *FLAGS accordingly to the platform.
-include $(srctree)/$(ARCH_DIR)/Makefile-os-$(OS)
+include $(ARCH_DIR)/Makefile-os-$(OS)
 
 KBUILD_CPPFLAGS += -I$(srctree)/$(HOST_DIR)/include \
 		   -I$(srctree)/$(HOST_DIR)/include/uapi \
@@ -101,8 +112,7 @@
 KBUILD_KCONFIG := $(HOST_DIR)/um/Kconfig
 
 archheaders:
-	$(Q)$(MAKE) -C '$(srctree)' KBUILD_SRC= \
-		ARCH=$(HEADER_ARCH) O='$(objtree)' archheaders
+	$(Q)$(MAKE) KBUILD_SRC= ARCH=$(HEADER_ARCH) archheaders
 
 archprepare: include/generated/user_constants.h