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/clear_vars.mk b/core/clear_vars.mk
index 63ae2a2..fb775c9 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -267,6 +267,11 @@
 LOCAL_GENERATED_SOURCES_$(HOST_OS):=
 LOCAL_REQUIRED_MODULES_$(HOST_OS):=
 
+LOCAL_SRC_FILES_$(HOST_OS)_$(HOST_ARCH):=
+ifdef HOST_2ND_ARCH
+LOCAL_SRC_FILES_$(HOST_OS)_$(HOST_2ND_ARCH):=
+endif
+
 LOCAL_SRC_FILES_32:=
 LOCAL_SRC_FILES_64:=
 LOCAL_SHARED_LIBRARIES_32:=