Add a command-line option of '-s', which indicates that newsyslog should

Add a command-line option of '-s', which indicates that newsyslog should
not send a signal to any processes.  Also add a config-file flag of 'N' or
'n', which indicates that the given logfile has no process which needs a
signal when it is rotated.  Both of these are based on changes NetBSD
has made, although the implementation is somewhat different.

PR:		bin/36553  (2nd half)
Reviewed by:	no objections on freebsd-arch
Obtained from:	NetBSD (in spirit, at least)
MFC after:	3 weeks