#include <boost/signals/trackable.hpp>
#include <boost/utility.hpp>
-#include <sys/time.h>
-#include <unistd.h>
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
#include <limits>
#include <map>