contrib function naming, and upgrade issues

Note that I'm talking here about the names of the C functions, not
the SQL names.

The existing hstore has some very dubious choices of function names
(for non-static functions) in the C code; functions like each(),
delete(), fetchval(), defined(), tconvert(), etc. which all look to me
like prime candidates for name collisions and consequent hilarity.

The patch I'm working on could include fixes for this; but there's an
obvious impact on anyone upgrading from an earlier version... is it
worth it?

-- 
Andrew (irc:RhodiumToad)