Include what we use.

Test: mma
Bug: None
Change-Id: I5f635659abb528ae6a9d1d9b33ae8a15e9f90ecf
Exempt-From-Owner-Approval: trivial cleanup
diff --git a/tests/tests/graphics/jni/android_graphics_cts_SyncTest.cpp b/tests/tests/graphics/jni/android_graphics_cts_SyncTest.cpp
index aeea02c..1379e48 100644
--- a/tests/tests/graphics/jni/android_graphics_cts_SyncTest.cpp
+++ b/tests/tests/graphics/jni/android_graphics_cts_SyncTest.cpp
@@ -17,6 +17,7 @@
 
 #define LOG_TAG "SyncTest"
 
+#include <errno.h>
 #include <poll.h>
 #include <unistd.h>