#include <glib/gi18n.h>
#include <sys/types.h>
#include <sys/wait.h>
+#if (defined(__DragonFly__) || defined (__NetBSD__) || defined (__FreeBSD__) || defined (__OpenBSD__))
+# include <sys/signal.h>
+#endif
#include "version.h"
#include "common/sylpheed.h"