(daemon_pidfile): Deleted #if:ed out file locking

code.
(daemon_started_by_init, daemon_started_by_inetd): Made static.
(daemon_detect): New function, split out from daemon_init.
(daemon_dup_null): Likewise.
(getdtablesize): New function, for systems that don't have it in
libc.
(daemon_close_fds): New function.
(daemon_init): New argument with the daemon mode. Split handling
of fd:s to the new functions daemon_dup_null and daemon_close_fds.

Rev: src/daemon.c:1.14