rs: Use -Wno-error - gcc 4.7 adds new warnings rs can't deal with

Change-Id: I38fe66629552d6f11be1bb69d5a93a05251614df
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
diff --git a/Android.mk b/Android.mk
index 42a018e..2a56378 100644
--- a/Android.mk
+++ b/Android.mk
@@ -2,6 +2,8 @@
 LOCAL_PATH:=$(call my-dir)
 
 rs_base_CFLAGS := -Werror -Wall -Wno-unused-parameter -Wno-unused-variable
+# For gcc 4.7, C++11 narrowing is a warning...
+rs_base_CFLAGS += -Wno-error
 ifeq ($(TARGET_BUILD_PDK), true)
   rs_base_CFLAGS += -D__RS_PDK__
 endif