Progress reporting for pg_verify_checksums

Hi,

my colleague Bernd Helmle recently added progress reporting to our
pg_checksums application[1]. I have now forward ported this to
pg_verify_checksums for the September commitfest, please see the
attached patch.

Here's the description:

This optionally prints the progress of pg_verify_checksums via read
kilobytes to the terminal with the new command line argument -P.

If -P was forgotten and pg_verify_checksums operates on a large cluster,
the caller can send SIGUSR1 to pg_verify_checksums to turn progress
status reporting on during runtime.


Michael

[1] https://github.com/credativ/pg_checksums/commit/2b691
-- 
Michael Banck
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