Make hba available to client code

Folks,

While investigating another project, namely adding pg_hba.conf support
to pgbouncer, I ran into a stumbling block others probably will, too:
the hba code is backend-only, which means that if I were to do this
as-is, I would be cooking a batch of very unappetizing copypasta.

I'm allergic to copypasta, so unless there are big objections, I'd
like to export those functions to make hba available to other code.

Objections?

Cheers,
David.
-- 
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
Skype: davidfetter      XMPP: david.fetter@gmail.com

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