Support custom RenderScript compiler

Change-Id: I85e38e84565e04f99dd26217f280274883dc322d
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index f947bf6..2d8c15a 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -102,6 +102,7 @@
 LOCAL_WARNINGS_ENABLE:=
 LOCAL_MANIFEST_FILE:=
 LOCAL_RENDERSCRIPT_INCLUDES:=
+LOCAL_RENDERSCRIPT_CC:=
 LOCAL_BUILD_HOST_DEX:=
 LOCAL_DEX_PREOPT:=
 LOCAL_PROTOC_OPTIMIZE_TYPE:= # lite(default),micro,full