art: convert makefiles to support multilib build

Convert makefiles to allow for building two architectures at the
same time.  More changes may be necessary to get the tests to
build.

Change-Id: I02ba11706b7e5b5592d76e43c167bcbf0e665b93
diff --git a/build/Android.executable.mk b/build/Android.executable.mk
index 5cf15be..e8d48e4 100644
--- a/build/Android.executable.mk
+++ b/build/Android.executable.mk
@@ -70,6 +70,7 @@
   ifeq ($$(art_target_or_host),target)
     LOCAL_CLANG := $(ART_TARGET_CLANG)
     LOCAL_CFLAGS += $(ART_TARGET_CFLAGS)
+    LOCAL_CFLAGS_x86 += $(ART_TARGET_CFLAGS_x86)
     ifeq ($$(art_ndebug_or_debug),debug)
       LOCAL_CFLAGS += $(ART_TARGET_DEBUG_CFLAGS)
     else
@@ -95,6 +96,10 @@
   LOCAL_ADDITIONAL_DEPENDENCIES += art/build/Android.executable.mk
 
   ifeq ($$(art_target_or_host),target)
+    LOCAL_MODULE_TARGET_ARCH := $(ART_SUPPORTED_ARCH)
+  endif
+
+  ifeq ($$(art_target_or_host),target)
     include $(BUILD_EXECUTABLE)
     ART_TARGET_EXECUTABLES := $(ART_TARGET_EXECUTABLES) $(TARGET_OUT_EXECUTABLES)/$$(LOCAL_MODULE)
   else # host