Add external/clang/lib/Headers as llvm-rs-cc's system header search path

Change-Id: I30257631d484491d9a8346205e411013c76c5a91
Bug: 2943524
diff --git a/core/java.mk b/core/java.mk
index c4baff5..e2eabed 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -136,8 +136,10 @@
 renderscript_intermediate := $(LOCAL_INTERMEDIATE_SOURCE_DIR)/renderscript
 
 # prepend the RenderScript system include path
-LOCAL_RENDERSCRIPT_INCLUDES := $(TOPDIR)frameworks/base/libs/rs/scriptc \
-    $(LOCAL_RENDERSCRIPT_INCLUDES)
+LOCAL_RENDERSCRIPT_INCLUDES := \
+     $(TOPDIR)external/clang/lib/Headers \
+     $(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)