Preliminary patch for FRONTEND

As many know, the FRONTEND usage of /src/port is very fragile. It
requires every binary that uses certain libpgport object files to create
its own version, which is very fragile, and could easily break if a
function call is added in a subrelease, especially on certain ports.

The following patch addresses this issue by making libpgport usable
unchanged by client applications, and makes a special server version for
the backend. This is much less fragile than trying to make sure you
hit every single binary that uses libpgport.

I originally tried abstracting out the #ifdef FRONTEND defines in pgport
but found that that wasn't easily done so making separate libraries was
cleaner.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
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