Add support for LOCAL_SRC_FILES_(host)_(arch)

For boringssl, which has architecture specific host assembly files

Bug: 23566667

Change-Id: Ia4602d28e93a1b3d1400cf95417b5e446c5fb84b
diff --git a/core/binary.mk b/core/binary.mk
index 7b629d8..cb045cc 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -154,7 +154,7 @@
 endif
 
 ifdef LOCAL_IS_HOST_MODULE
-my_src_files += $(LOCAL_SRC_FILES_$($(my_prefix)OS))
+my_src_files += $(LOCAL_SRC_FILES_$($(my_prefix)OS)) $(LOCAL_SRC_FILES_$($(my_prefix)OS)_$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH))
 my_static_libraries += $(LOCAL_STATIC_LIBRARIES_$($(my_prefix)OS))
 my_shared_libraries += $(LOCAL_SHARED_LIBRARIES_$($(my_prefix)OS))
 my_cflags += $(LOCAL_CFLAGS_$($(my_prefix)OS))