64-bit host multilib build.

Bug: 13751317
Change-Id: I98c0d593e441add79d51ec1b690c4abd3489a8cf
diff --git a/build/Android.common.mk b/build/Android.common.mk
index 39601e4..cc600bd 100644
--- a/build/Android.common.mk
+++ b/build/Android.common.mk
@@ -37,11 +37,7 @@
 ART_BUILD_HOST_NDEBUG ?= $(WITH_HOST_DALVIK)
 ART_BUILD_HOST_DEBUG ?= $(WITH_HOST_DALVIK)
 
-ifeq ($(BUILD_HOST_64bit),)
-ART_HOST_ARCH := x86
-else
-ART_HOST_ARCH := x86_64
-endif
+ART_HOST_ARCH := $(HOST_ARCH)
 
 ifeq ($(ART_BUILD_TARGET_NDEBUG),false)
 $(info Disabling ART_BUILD_TARGET_NDEBUG)