Avoid deadlocks during insertion into SP-GiST indexes.

SP-GiST's original scheme for avoiding deadlocks during concurrent index
insertions doesn't work, as per report from Hailong Li, and there isn't any
evident way to make it work completely.  We could possibly lock individual
inner tuples instead of their whole pages, but preliminary experimentation
suggests that the performance penalty would be huge.  Instead, if we fail
to get a buffer lock while descending the tree, just restart the tree
descent altogether.  We keep the old tuple positioning rules, though, in
hopes of reducing the number of cases where this can happen.

Teodor Sigaev, somewhat edited by Tom Lane
Stamp HEAD as 9.4devel.

Let the hacking begin ...
Stamp shared-library minor version numbers for 9.4.
Update RELEASE_CHANGES to describe library version bumping more fully.
Add :client_id automatic variable for custom pgbench scripts.

This makes it easier to write custom scripts that have different logic for
each client.

Gurjeet Singh, with some changes by me.
Be consistent about #define'ing configure symbols as "1" not empty.

This is just neatnik-ism, since all the tests in the code are #ifdefs,
but we shouldn't specify symbols as "Define to 1 ..." and then not
actually define them that way.
Use SA_RESTART for all signals, including SIGALRM.

The exclusion of SIGALRM dates back to Berkeley days, when Postgres used
SIGALRM in only one very short stretch of code.  Nowadays, allowing it to
interrupt kernel calls doesn't seem like a very good idea, since its use
for statement_timeout means SIGALRM could occur anyplace in the code, and
there are far too many call sites where we aren't prepared to deal with
EINTR failures.  When third-party code is taken into consideration, it
seems impossible that we ever could be fully EINTR-proof, so better to
use SA_RESTART always and deal with the implications of that.  One such
implication is that we should not assume pg_usleep() will be terminated
early by a signal.  Therefore, long sleeps should probably be replaced
by WaitLatch operations where practical.

Back-patch to 9.3 so we can get some beta testing on this change.
Fix pg_restore -l with the directory archive to display the correct format name.

Back-patch to 9.1 where the directory archive was introduced.
Use WaitLatch, not pg_usleep, for delaying in pg_sleep().

This avoids platform-dependent behavior wherein pg_sleep() might fail to be
interrupted by statement timeout, query cancel, SIGTERM, etc.  Also, since
there's no reason to wake up once a second any more, we can reduce the
power consumption of a sleeping backend a tad.

Back-patch to 9.3, since use of SA_RESTART for SIGALRM makes this a bigger
issue than it used to be.
Fix description of archive format which pg_restore -j supports.
Add buffer_std flag to MarkBufferDirtyHint().

MarkBufferDirtyHint() writes WAL, and should know if it's got a
standard buffer or not. Currently, the only callers where buffer_std
is false are related to the FSM.

In passing, rename XLOG_HINT to XLOG_FPI, which is more descriptive.

Back-patch to 9.3.
psql: Re-allow -1 together with -c or -l
Fix docs on lock level for ALTER TABLE VALIDATE

ALTER TABLE .. VALIDATE CONSTRAINT previously
gave incorrect details about lock levels and
therefore incomplete reasons to use the option.

Initial bug report and fix from Marko Tiikkaja
Reworded by me to include comments by Kevin Grittner
Fix the create_index regression test for Danish collation.

In Danish collations, there are letter combinations which sort
higher than 'Z'.  A test for values > 'WA' was picking up rows
where the value started with 'AA', causing the test to fail.

Backpatch to 9.2, where the failing test was added.

Per report from Svenne Krap and analysis by Jeff Janes
Modernize entab source code
Remove halt.c, improve comments, rename manual page file.
Support TB (terabyte) memory unit in GUC variables.

Patch by Simon Riggs, reviewed by Jeff Janes and me.
initdb: Add blank line before output about checksums

This maintains the logical grouping of the output better.
Further update CREATE FUNCTION documentation about argument names

More languages than SQL and PL/pgSQL actually support parameter names.