Enable -Wall/-Werror with LOCAL_RENDERSCRIPT_FLAGS.

Change-Id: Ia2a058e6711839d89072c2e96f0c60aa4cedda6b
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index d9f3372..3a04b7b 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -107,6 +107,7 @@
 LOCAL_RENDERSCRIPT_INCLUDES:=
 LOCAL_RENDERSCRIPT_INCLUDES_OVERRIDE:=
 LOCAL_RENDERSCRIPT_CC:=
+LOCAL_RENDERSCRIPT_FLAGS:=
 LOCAL_RENDERSCRIPT_TARGET_API:=
 LOCAL_BUILD_HOST_DEX:=
 LOCAL_DEX_PREOPT:= # '',true,false,nostripping
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) \
diff --git a/core/java.mk b/core/java.mk
index 1cde62b..0cc0762 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -152,6 +152,11 @@
 LOCAL_RENDERSCRIPT_CC := $(LLVM_RS_CC)
 endif
 
+# Turn on all warnings and warnings as errors for RS compiles.
+# This can be disabled with LOCAL_RENDERSCRIPT_FLAGS := -Wno-error
+renderscript_flags := -Wall -Werror
+renderscript_flags += $(LOCAL_RENDERSCRIPT_FLAGS)
+
 # prepend the RenderScript system include path
 ifneq ($(filter-out current,$(LOCAL_SDK_VERSION)),)
 LOCAL_RENDERSCRIPT_INCLUDES := \
@@ -171,6 +176,7 @@
 
 $(RenderScript_file_stamp): PRIVATE_RS_INCLUDES := $(LOCAL_RENDERSCRIPT_INCLUDES)
 $(RenderScript_file_stamp): PRIVATE_RS_CC := $(LOCAL_RENDERSCRIPT_CC)
+$(RenderScript_file_stamp): PRIVATE_RS_FLAGS := $(renderscript_flags)
 $(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.