tools/lib/: new helper function for daemonification

- include/daemon.h (daemonize), lib/daemon.c: shed all ties with the
  process' previous surroundings
- lib/Makefile (OBJS): added daemon.o

tools/include/daemon.h

@@ -0,0 +1,22 @@
+/*
+ * include/daemon.h - Helper functions for proper daemonification
+ *
+ * Written 2011 by Werner Almesberger
+ * Copyright 2011 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#ifndef DAEMON_H
+#define DAEMON_H
+
+#include <unistd.h>
+
+
+pid_t daemonize(void);
+
+#endif /* !DAEMON_H */