Include what you use

Change-Id: I1967861f383bb5ed6743fb69e3bd439907ed7033
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 15dd408..384bd25 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -23,7 +23,9 @@
 #include "Configuration.h"
 #include <math.h>
 #include <fcntl.h>
+#include <linux/futex.h>
 #include <sys/stat.h>
+#include <sys/syscall.h>
 #include <cutils/properties.h>
 #include <media/AudioParameter.h>
 #include <media/AudioResamplerPublic.h>