audio: Access header files through header libs

Access header files through header libs which are not accessed
directly.

Change-Id: Ia98e31fd43d56e9bb4786ee00de49961047808d4
diff --git a/visualizer/Android.mk b/visualizer/Android.mk
index 988620c..61d37da 100644
--- a/visualizer/Android.mk
+++ b/visualizer/Android.mk
@@ -27,6 +27,8 @@
     LOCAL_CFLAGS += -DCAPTURE_DEVICE=7
 endif
 
+LOCAL_HEADER_LIBRARIES := libsystem_headers \
+                          libhardware_headers
 LOCAL_SHARED_LIBRARIES := \
 	libcutils \
 	liblog \