duplicate function oid symbols

Hi,

I noticed that the table AM abstraction introduced the symbol
HEAP_TABLE_AM_HANDLER_OID, although we already have a convention for
defining symbols automatically for builtin functions, which in this case is
(currently unused) F_HEAP_TABLEAM_HANDLER.

It seems a wart to have two symbols for the same function (seemingly
accidentally). I suppose it's unacceptable to remove the non-standard
symbol since it's been referred to in code for a while now. We could remove
the unused (in core anyway) standard one by arranging fmgroids.h to use
explicit symbols from pg_proc.dat where they exist, as well as prevent such
symbols from being emitted into pg_proc_d.h. But then again there is
no guarantee the standard symbol is not being used elsewhere. Thoughts?

-- 
John Naylor
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company