Add back builds for libaaudio examples

These will actually get installed as tests in /data/nativetest{,64}/...,
instead of into the /system/bin directory.

Test: mmma frameworks/av/media/libaaudio
Change-Id: I41e077e21e3d5c76f0fd5b4f21f7377a0c293740
diff --git a/media/libaaudio/examples/Android.bp b/media/libaaudio/examples/Android.bp
index f2e00a7..639fab2 100644
--- a/media/libaaudio/examples/Android.bp
+++ b/media/libaaudio/examples/Android.bp
@@ -1,4 +1,6 @@
+subdirs = ["*"]
+
 cc_library_headers {
     name: "libaaudio_example_utils",
-    export_include_dirs: ["."],
+    export_include_dirs: ["utils"],
 }