Now slang supports "-I" options.

Change-Id: I32aef6c913d9d30f9982a593397145f1562aecf9
diff --git a/core/java.mk b/core/java.mk
index da53a5c..71439f7 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -105,6 +105,11 @@
 renderscript_sources_fullpath := $(addprefix $(LOCAL_PATH)/, $(renderscript_sources))
 RenderScript_file_stamp := $(LOCAL_INTERMEDIATE_SOURCE_DIR)/RenderScript.stamp
 
+# prepend the RenderScript system include path
+LOCAL_RENDERSCRIPT_INCLUDES := $(TOPDIR)frameworks/base/libs/rs/scriptc \
+    $(LOCAL_RENDERSCRIPT_INCLUDES)
+
+$(RenderScript_file_stamp): PRIVATE_RS_INCLUDES := $(LOCAL_RENDERSCRIPT_INCLUDES)
 $(RenderScript_file_stamp): PRIVATE_RS_SOURCE_FILES := $(renderscript_sources_fullpath)
 # By putting the generated java files into $(LOCAL_INTERMEDIATE_SOURCE_DIR), they will be
 # automatically found by the java compiling function transform-java-to-classes.jar.