Add built/libs/* to root.bp

Change-Id: I05af556dde2df5a1ef38d1cc9eb557c8e2729490
diff --git a/root.bp b/root.bp
index 2b72cfa..822e65b 100644
--- a/root.bp
+++ b/root.bp
@@ -8,6 +8,7 @@
 optional_subdirs = [
     "bionic",
     "build/kati",
+    "build/libs/*",
     "build/tools/*",
     "dalvik",
     "external/*",