Re: backend type in log_line_prefix?

I like these patches; the first two are nice cleanup.

My only gripe is that pgstat_get_backend_desc() is not really a pgstat
function; I think it should have a different name with a prototype in
miscadmin.h (next to the enum's new location, which I would put
someplace near the "pmod.h" comment rather than where you put it;
perhaps just above the AuxProcType definition), and implementation
probably in miscinit.c.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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