Fix Fuchsia build.

Add unistd.h for close().

Change-Id: Ic3ed99266d206c4aecb4c51e0e5f18b660a1d53f
diff --git a/system/OpenglSystemCommon/HostConnection.cpp b/system/OpenglSystemCommon/HostConnection.cpp
index 7a888d0..72ea1f0 100644
--- a/system/OpenglSystemCommon/HostConnection.cpp
+++ b/system/OpenglSystemCommon/HostConnection.cpp
@@ -67,6 +67,7 @@
 #include "TcpStream.h"
 #include "ThreadInfo.h"
 #include <gralloc_cb_bp.h>
+#include <unistd.h>
 
 #ifdef VIRTIO_GPU