MFC r266209 by gnn:

  Add a command line argument (-l) to end event collection after some
  number of seconds. The number of seconds may be a fraction.

Relnotes:	yes
Approved by:	re
Document r267411, pmcstat(8) '-l' flag.

Approved by:	re (implicit)
Sponsored by:	The FreeBSD Foundation
MFC r266208: Speed up pmcstat by improving string hash

  In one case generating callgraph output from a 24MB system-wide sampling
  data file took 17.4 seconds on average.  Profiling showed pmcstat
  spending a lot of time in strcmp, due to hash collisions.

  Replacing the XOR-only hash with FNV-1a reduces the run time for my
  test by 40%.

Approved by:	re
MFC r266403: Update the date on the manual page.

Approved by:	re
MFC r267326, r267327:

r267326:
  Add empty pkg-stage file to CLEANFILES if WITH_DVD=1.

r267327:
  Fix indentation level.

Approved by:	re (marius)
Sponsored by:	The FreeBSD Foundation