[Android.bp] soong_config for ARC++

Test: compile
Bug: 64500663

Change-Id: Id81ea4926b40e739fe16c9c71a9895556a504e9e
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 6f5ca4e..32e9ae0 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -118,6 +118,7 @@
 $(call add_json_bool, MinimizeJavaDebugInfo,             $(filter true,$(PRODUCT_MINIMIZE_JAVA_DEBUG_INFO)))
 
 $(call add_json_bool, UseGoma,                           $(filter-out false,$(USE_GOMA)))
+$(call add_json_bool, Arc,                               $(filter true,$(TARGET_ARC)))
 
 $(call add_json_str,  DistDir,                           $(if $(dist_goal), $(DIST_DIR)))