Turn FORTIFY back on for the RS support library.

Bug: http://b/21084950

This started out disabled a long time ago, because of problems with the
NDK implementation (and Clang, I assume). It works now, so there is no
need to keep it disabled.

Change-Id: I43cee37d9ec9789701fa889794d6e321cbca3c41
diff --git a/v8/renderscript/jni/Android.mk b/v8/renderscript/jni/Android.mk
index 2d382b1..d6a800d 100644
--- a/v8/renderscript/jni/Android.mk
+++ b/v8/renderscript/jni/Android.mk
@@ -14,7 +14,7 @@
 	frameworks/rs/cpp \
 	frameworks/rs/driver
 
-LOCAL_CFLAGS += -Wno-unused-parameter -U_FORTIFY_SOURCE -Werror
+LOCAL_CFLAGS += -Wno-unused-parameter -Werror
 LOCAL_CFLAGS += -DRS_COMPATIBILITY_LIB -std=c++11
 
 LOCAL_MODULE:= libRSSupportIO
@@ -44,7 +44,7 @@
 	frameworks/rs \
 	frameworks/rs/cpp
 
-LOCAL_CFLAGS += -Wno-unused-parameter -U_FORTIFY_SOURCE -Werror -std=c++11
+LOCAL_CFLAGS += -Wno-unused-parameter -Werror -std=c++11
 
 LOCAL_MODULE:= librsjni
 LOCAL_MODULE_TAGS := optional