Suppress implicit-fallthrough warnings in audioflinger etc.

Add FALLTHROUGH_INTENDED for clang compiler.

Bug: 112564944
Test: build with global -Wimplicit-fallthrough.
Change-Id: I8875bc7ed073aae84d5df97eb39c8c745ca627ef
diff --git a/services/audiopolicy/enginedefault/Android.mk b/services/audiopolicy/enginedefault/Android.mk
index cbbe306..837d5bb 100644
--- a/services/audiopolicy/enginedefault/Android.mk
+++ b/services/audiopolicy/enginedefault/Android.mk
@@ -34,6 +34,8 @@
 LOCAL_MODULE := libaudiopolicyenginedefault
 LOCAL_MODULE_TAGS := optional
 
+LOCAL_HEADER_LIBRARIES := libbase_headers
+
 LOCAL_STATIC_LIBRARIES := \
     libaudiopolicycomponents \