diff --git a/core/binary.mk b/core/binary.mk
index d6ccfbf..61026d2 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -575,7 +575,9 @@
       NOTICE-$(if $(LOCAL_IS_HOST_MODULE),HOST,TARGET)-STATIC_LIBRARIES-$(lib))
 
 # Default is -fno-rtti.
-LOCAL_RTTI_FLAG ?= -fno-rtti
+ifeq ($(strip $(LOCAL_RTTI_FLAG)),)
+LOCAL_RTTI_FLAG := -fno-rtti
+endif
 
 ###########################################################
 # Rule-specific variable definitions
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index ab6efd4..bc085f5 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -42,6 +42,7 @@
 LOCAL_ASFLAGS:=
 LOCAL_CFLAGS:=
 LOCAL_CPPFLAGS:=
+LOCAL_RTTI_FLAG:=
 LOCAL_C_INCLUDES:=
 LOCAL_LDFLAGS:=
 LOCAL_LDLIBS:=