Replace appendPQExpBuffer(..., <constant>) with appendPQExpBufferStr

Arguably makes the code a bit more readable, and might give a small
performance gain.

David Rowley
Spell SQL keywords in uppercase in pg_dump's query.

The server won't care, but let's be consistent.

David Rowley.
unaccent:  Revert patch 9299f6179838cef8aa1123f6fb76f0d3d6f2decc

The reverted patch to change functions from strict to immutable was
incorrect and needs additional research.
pg_upgrade: Report full disk better

Previously, pg_upgrade would abort copy_file() on a short write without
setting errno, which the caller would report as an error with the
message "Success".  We assume ENOSPC in that case, as we do elsewhere in
the code.  Also set errno in some other error cases in copy_file() to
avoid bogus "Success" error messages.

This was broken in 6b711cf37c228749b6a8cef50e16e3c587d18dd4, so 9.2 and
before are OK.
Add tab completion for \pset in psql.

Pavel Stehule, reviewed by Ian Lawrence Barwick
pg_upgrade:  avoid ALTER COLUMN TYPE on inherited columns

This only affects upgrades from 8.3 currently, and is harmless as the
child just generates an error in the script, but we should get it right
in case we ever need this for more complex uses.

Per report from Peter Eisentraut
docs:  update page format to specify page checksum field

Backpatch to 9.3

Per report from Steffen Hildebrandt
ecpg: Split off mmfatal() from mmerror()

This allows decorating mmfatal() with noreturn compiler hints, leading
to better diagnostics.
Further GIN refactoring.

Merge some functions that were always called together. Makes the code
little bit more readable.
Refactor the internal GIN B-tree interface for forming a downlink.

This creates a new gin-btree callback function for creating a downlink for
a page. Previously, ginxlog.c duplicated the logic used during normal
operation.
More GIN refactoring.

Split off the portion of ginInsertValue that inserts the tuple to current
level into a separate function, ginPlaceToPage. ginInsertValue's charter
is now to recurse up the tree to insert the downlink, when a page split is
required.

This is in preparation for a patch to change the way incomplete splits are
handled, which will need to do these operations separately. And IMHO makes
the code more readable anyway.
Merge remote-tracking branch 'origin/master' into table_functions_record