Add default arch to fix compiling outside emake

Makefile

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 export FIRMWARE_ARCH
 
 export CC ?= gcc
 export CXX ?= g++
 export CFLAGS = -Wall -Werror
 
 ifeq (${DEBUG},)
 CFLAGS += -O3
 else
 CFLAGS += -O0 -g
 endif
 
 # Override CC and CFLAGS only if FIRMWARE_CONFIG_PATH is not empty, but we
 # wish to preserve -D flags (so move all -D flags after this).
 ifneq (${FIRMWARE_CONFIG_PATH},)
 include ${FIRMWARE_CONFIG_PATH}
 endif
 
+# Fix compiling directly on host (outside of emake)
+ifeq ($(ARCH),)
+export ARCH=amd64
+endif
+
 ifeq ($(FIRMWARE_ARCH),)
 CFLAGS += -DCHROMEOS_ENVIRONMENT
 endif
 
 ifneq (${DEBUG},)
 CFLAGS += -DVBOOT_DEBUG
 endif
 
 ifeq (${DISABLE_NDEBUG},)
 CFLAGS += -DNDEBUG
@@ skipping 40 matching lines @@
         $(MAKE) -C cgpt install
 
 runtests:
         $(MAKE) -C tests runtests
 
 rbtest:
         $(MAKE) -C tests rbtest
 
 runbmptests:
         $(MAKE) -C tests runbmptests