This unifies a bunch of ugly #ifdef's in one place.  Per discussion,
we only need this where HAVE_UNIX_SOCKETS, so no need to cover Windows.

Marko Kreen, some adjustment by Tom Lane

It turns out the reason we hadn't found out about the portability issues
with our credential-control-message code is that almost no modern platforms
use that code at all; the ones that used to need it now offer getpeereid(),
which we choose first.  The last holdout was NetBSD, and they added
getpeereid() as of 5.0.  So far as I can tell, the only live platform on
which that code was being exercised was Debian/kFreeBSD, ie, FreeBSD kernel
with Linux userland --- since glibc doesn't provide getpeereid(), we fell
back to the control message code.  However, the FreeBSD kernel provides a
LOCAL_PEERCRED socket parameter that's functionally equivalent to Linux's
SO_PEERCRED.  That is both much simpler to use than control messages, and
superior because it doesn't require receiving a message from the other end
at just the right time.

Therefore, add code to use LOCAL_PEERCRED when necessary, and rip out all
the credential-control-message code in the backend.  (libpq still has such
code so that it can still talk to pre-9.1 servers ... but eventually we can
get rid of it there too.)  Clean up related autoconf probes, too.

This means that libpq's requirepeer parameter now works on exactly the same
platforms where the backend supports peer authentication, so adjust the
documentation accordingly.

This is reported to be necessary on some versions of that OS.  In service
of this, cause PGAC_PROG_CC_CFLAGS_OPT to reject switches that result in
compiler warnings, since on yet other versions of that OS, the switch does
nothing except provoke a warning.

Report and patch by Ibrar Ahmed, further tweaking by me.

We need at least version 2.0.93, so probe for a function that was added
in that version.

Kaigai Kohei

With some compilers such as Clang and ICC emulating GCC, using a
version string of the form "GCC $version" can be quite misleading.
Also, a great while ago, the version output from gcc --version started
including the string "gcc", so it is redundant to repeat that.  In
order to support ancient GCC versions, we now prefix the result with
"GCC " only if the version output does not start with a letter.

These functions should take a pg_locale_t, not a collation OID, and should
call mbstowcs_l/wcstombs_l where available.  Where those functions are not
available, temporarily select the correct locale with uselocale().

This change removes the bogus assumption that all locales selectable in
a given database have the same wide-character conversion method; in
particular, the collate.linux.utf8 regression test now passes with
LC_CTYPE=C, so long as the database encoding is UTF8.

I decided to move the char2wchar/wchar2char functions out of mbutils.c and
into pg_locale.c, because they work on wchar_t not pg_wchar_t and thus
don't really belong with the mbutils.c functions.  Keeping them where they
were would have required importing pg_locale_t into pg_wchar.h somehow,
which did not seem like a good plan.

Mapped to NetBSD, the closest existing match.  (Even though DragonFly
BSD is derived from FreeBSD, the shared library version numbering
matches NetBSD, and the rest is mostly the same among all BSD
variants.)

per "Rumko"

This adds collation support for columns and domains, a COLLATE clause
to override it per expression, and B-tree index support.

Peter Eisentraut
reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch

This is still pretty rough - among other things, the documentation
needs work, and the messages need a visit from the style police -
but this gets the basic framework in place.

KaiGai Kohei

The mingw people don't appear to care about compatibility with non-GNU
versions of getopt, so force use of our own copy of getopt on Windows.
Also, ensure that we make use of optreset when using our own copy.

Per report from Andrew Dunstan.  Back-patch to all versions supported
on Windows.

wait until it is set. Latches can be used to reliably wait until a signal
arrives, which is hard otherwise because signals don't interrupt select()
on some platforms, and even when they do, there's race conditions.

On Unix, latches use the so called self-pipe trick under the covers to
implement the sleep until the latch is set, without race conditions. On
Windows, Windows events are used.

Use the new latch abstraction to sleep in walsender, so that as soon as
a transaction finishes, walsender is woken up to immediately send the WAL
to the standby. This reduces the latency between master and standby, which
is good.

Preliminary work by Fujii Masao. The latch implementation is by me, with
helpful comments from many people.

(And there was much rejoicing.)

tag beta3

linking both executables and shared libraries, and we add on LDFLAGS_EX when
linking executables or LDFLAGS_SL when linking shared libraries.  This
provides a significantly cleaner way of dealing with link-time switches than
the former behavior.  Also, make sure that the various platform-specific
%.so: %.o rules incorporate LDFLAGS and LDFLAGS_SL; most of them missed that
before.  (I did not add these variables for the platforms that invoke $(LD)
directly, however.  It's not clear if we can do that safely, since for the
most part we assume these variables use CC command-line syntax.)

Per gripe from Aaron Swenson and subsequent investigation.

tag 9.0beta2

Added a configure test for "long long" datatypes. So far this is only used in ecpg and replaces the old test that was kind of hackish.

Should fix buildfarm failures.

tag for 9.0beta1

(hope I got 'em all).  Per discussion, this release will be 9.0 not 8.5.

compilers, by applying a configure check to see if the compiler will accept
an unreferenced "static inline foo ..." function without warnings.  It is
believed that such warnings are the only reason not to declare inlined
functions in headers, if the compiler understands "inline" at all.

Kurt Harriman

posix_fadvise and other file-related functions can depend on _LARGEFILE_SOURCE
and/or _FILE_OFFSET_BITS.  Per report from Robert Treat.

Back-patch to 8.4.  This has been wrong all along, but we weren't really using
posix_fadvise in anger before, and AC_FUNC_FSEEKO seems to mask the issue well
enough for that function.

provide a working 64-bit integer datatype.  As recently noted, we've been
broken on such platforms since early in the 8.4 development cycle.  Since
it took nearly two years for anyone to even notice, it seems that the
rationale for continuing to support such platforms has reached the point
of non-existence.  Rather than thrashing around to try to make it work
again, we'll just admit up front that this no longer works.

Back-patch to 8.4 since that branch is also broken.

We should go around to remove INT64_IS_BUSTED support, but just in HEAD,
so that seems like material for a separate commit.

This is more in keeping with modern practice, and is a first step towards
porting to Win64 (which has sizeof(pointer) > sizeof(long)).

Tsutomu Yamada, Magnus Hagander, Tom Lane