emacs.samples: Reliably override ".dir-locals.el".

Back-patch to 9.4, where .dir-locals.el was introduced.
Adjust 9.4 release notes.

Back-patch to 9.4.
Harden pg_filenode_relation test against concurrent DROP TABLE.

Per buildfarm member prairiedog.  Back-patch to 9.4, where the test was
introduced.

Reviewed by Tom Lane.
Change the signature of rm_desc so that it's passed a XLogRecord.

Just feels more natural, and is more consistent with rm_redo.
Add mkdtemp() to libpgport.

This function is pervasive on free software operating systems; import
NetBSD's implementation.  Back-patch to 8.4, like the commit that will
harness it.
Secure Unix-domain sockets of "make check" temporary clusters.

Any OS user able to access the socket can connect as the bootstrap
superuser and proceed to execute arbitrary code as the OS user running
the test.  Protect against that by placing the socket in a temporary,
mode-0700 subdirectory of /tmp.  The pg_regress-based test suites and
the pg_upgrade test suite were vulnerable; the $(prove_check)-based test
suites were already secure.  Back-patch to 8.4 (all supported versions).
The hazard remains wherever the temporary cluster accepts TCP
connections, notably on Windows.

As a convenient side effect, this lets testing proceed smoothly in
builds that override DEFAULT_PGSOCKET_DIR.  Popular non-default values
like /var/run/postgresql are often unwritable to the build user.

Security: CVE-2014-0067
Use type pgsocket for Windows pipe emulation socket calls

This prevents several compiler warnings on Windows.
Avoid recursion when processing simple lists of AND'ed or OR'ed clauses.

Since most of the system thinks AND and OR are N-argument expressions
anyway, let's have the grammar generate a representation of that form when
dealing with input like "x AND y AND z AND ...", rather than generating
a deeply-nested binary tree that just has to be flattened later by the
planner.  This avoids stack overflow in parse analysis when dealing with
queries having more than a few thousand such clauses; and in any case it
removes some rather unsightly inconsistencies, since some parts of parse
analysis were generating N-argument ANDs/ORs already.

It's still possible to get a stack overflow with weirdly parenthesized
input, such as "x AND (y AND (z AND ( ... )))", but such cases are not
mainstream usage.  The maximum depth of parenthesization is already
limited by Bison's stack in such cases, anyway, so that the limit is
probably fairly platform-independent.

Patch originally by Gurjeet Singh, heavily revised by me
Revert accidental change of WAL_DEBUG default.

Oops.