psql now returns error from queries and errors files, so ignore return code.

In particular, no more compiled-in default for PGDATA or LIBDIR.  Commands
that need them need either invocation options or environment variables.
PGPORT default is hardcoded as 5432, but overrideable with options or
environment variables.

Requested by Bryan

explicitly.

Changes:

        * Unique index capability works using the syntax 'create unique
          index'.

        * Duplicate OID's in the system tables are removed.  I put
          little scripts called 'duplicate_oids' and 'find_oid' in
          include/catalog that help to find and remove duplicate OID's.
          I also moved 'unused_oids' from backend/catalog to
          include/catalog, since it has to be in the same directory
          as the include files in order to work.

        * The backend tries converting the name of a function or aggregate
          to all lowercase if the original name given doesn't work (mostly
          for compatibility with ODBC).

        * You can 'SELECT NULL' to your heart's content.

        * I put my _bt_updateitem fix in instead, which uses
          _bt_insertonpg so that even if the new key is so big that
          the page has to be split, everything still works.

        * All literal references to system catalog OID's have been
          replaced with references to define'd constants from the catalog
          header files.

        * I added a couple of node copy functions.  I think this was a
          preliminary attempt to get rules to work.

miscadmin.h.

to be sleazy and reach into other subsystems' directories.  First entry in
this directory is the PG_VERSION file interface, which must be used by the
backend and also the pg_version program (which is used by initdb).

|After sending my previous changes I found one more thing in Makefile.global.
|Any tests should be done after including Makefile.custom or else there
|won't be anything, particularly the port name, to base the tests on.
|
-----

more changes to makefile.global from D'Arcy

    following is the patch to libpq's large object interface that
    removes the requirement to  include  fmgr.h  into  fe-lobj.c.
    The  large object interface now ask's the backend to tell the
    OID's of all the required functions in pg_proc.

From: wieck@sapserv.debis.de (Jan Wieck)

called, it dumps core...

ABORT_ON_ASSERT must be defined, as I don't know if this is the correct
way to do this...