Add WITH_ART

(cherry picked from commit 6b7a0d2f1ff90d24e3ade9ccf82a084f5f999c1f)

Change-Id: If6e208f9fc859f31da2cd71fdc1ddbe1fc1ed7aa
diff --git a/buildspec.mk.default b/buildspec.mk.default
index 2f84016..397194c 100644
--- a/buildspec.mk.default
+++ b/buildspec.mk.default
@@ -104,6 +104,11 @@
 #ENABLE_SVG:=false
 endif
 
+# To enable ART define WITH_ART:=true
+ifndef WITH_ART
+#WITH_ART:=true
+endif
+
 # when the build system changes such that this file must be updated, this
 # variable will be changed.  After you have modified this file with the new
 # changes (see buildspec.mk.default), update this to the new value from