`J' flag means that newsyslog should wait for previously started compression
jobs to complete before starting a new one for this entry. When it is used
along with the `G' flag, in the case when several logfiles match the pattern
and should be compressed, the newsyslog will compress logs one by one,
ensuring that only one compression job is running at a time.
This prevents newsyslog(8) from overloading system by starting several
compression jobs on big files simultaneously.
Sponsored by: Porta Software Ltd
MFC after: 2 weeks
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