Make libqcomvisualizer build with the VNDK.

When the vndk is enabled (BOARD_VNDK_VERSION=current),
vendor libraries must only link against vendor variants
in the build system. This means that they receive restricted
sets of headers and that automatic global headers are restricted.

Test: build libqcomvisualizer with BOARD_VNDK_VERSION=current
Bug: 37342627
Change-Id: I7f17946754091ac3a71ccc6451429bb1cd60d13b
diff --git a/visualizer/Android.mk b/visualizer/Android.mk
index 29a093e..3b856e3 100644
--- a/visualizer/Android.mk
+++ b/visualizer/Android.mk
@@ -27,6 +27,8 @@
 	libdl \
 	libtinyalsa
 
+LOCAL_HEADER_LIBRARIES := libhardware_headers
+
 LOCAL_MODULE_RELATIVE_PATH := soundfx
 LOCAL_MODULE:= libqcomvisualizer
 LOCAL_MODULE_OWNER := qcom