Enable -Wall/-Werror with LOCAL_RENDERSCRIPT_FLAGS.

Change-Id: Ia2a058e6711839d89072c2e96f0c60aa4cedda6b
diff --git a/core/definitions.mk b/core/definitions.mk
index 53f22c7..154c026 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -802,6 +802,7 @@
   -d $(PRIVATE_RS_OUTPUT_DIR) \
   -a $@ -MD \
   $(addprefix -target-api , $(PRIVATE_RS_TARGET_API)) \
+  $(PRIVATE_RS_FLAGS) \
   $(foreach inc,$(PRIVATE_RS_INCLUDES),$(addprefix -I , $(inc))) \
   $(PRIVATE_RS_SOURCE_FILES)
 #$(hide) $(LLVM_RS_LINK) \