This upgrades the configure infrastructure to the latest Autoconf version.
Some notable news are:
 - The workaround for the broken fseeko() test is gone.
 - Checking for unknown options is now provided by Autoconf itself.
 - Fixes for Mac OS X

used to work as intended, but got broken some time ago (a quoted empty string
is not an empty string), and got broken some more by the changes to generate
ecpg's preproc.y automatically.  Given all the unprotected uses of $(PERL)
elsewhere, it seems best to make use of the $(missing) script rather than
trying to ensure each such use is protected individually.  Also fix various
bits of documentation that omitted to mention Perl as a requirement for
building from a CVS pull.  Per a complaint from Robert Haas.

print foo --> print(foo)
string.join(...) --> ' '.join(...)

These changes are backward compatible.

The actual plpython module appears to need significant updates to support
Python 3.0, though.  This change just relieves interested developers from
having to deal with Autoconf.

page build target.  This covers from-source, Debian, and Fedora
installation variants.

Detect and error out on inability to get proper linkage information required for plperl, usually due to absence of perl ExtUtils::Embed module. Backpatch as far as 8.1.

align strings in the --help output.  Do this through our abstraction layer
to eliminate redundancy and randomness in configure.in.

change build system to use only Bison.  Simplify build rules, make file names
uniform.  Don't build the token table header file where it is not needed.

noncomplying cases to be future-proof.

numbered program.  Per persistent buildfarm failures.

Tom Lane

This is required because the value is substituted into the pltcl_*mod
scripts.

vintage Linux is even more broken than we realized: a link to libreadline
will succeed, and fail only at runtime.  It seems that an AC_TRY_RUN test
is the only reliable way to check whether this is really safe.  Per report
from Tatsuo.

GNU gettext before 0.10.36 does not have that function, and is generally too
incomplete to be usable.

libreadline.  What we will do for compatibility :-(

shared libraries.  We've tried this before and had problems with libreadline
not linking properly on some platforms, but that seems to be a libreadline
bug that may have been fixed by now.  In any case, it's early enough in the
8.4 devel cycle that we can afford to have some transient breakage while
we work out any portability problems.

On Darwin, we try -Wl,-dead_strip_dylibs, which seems to be the equivalent
incantation there.

uses of the long-deprecated float32 in contrib/seg; the definitions themselves
are still there, but no longer used.  fmgr/README updated to match.

I added a CREATE FUNCTION to account for existing seg_center() code in seg.c
too, and some tests for it and the neighbor functions.  At the same time,
remove checks for NULL which are not needed (because the functions are declared
STRICT).

I had to do some adjustments to contrib's btree_gist too.  The choices for
representation there are not ideal for changing the underlying types :-(

Original patch by Zoltan Boszormenyi, with some adjustments by me.

- Change configure.in to use Autoconf 2.61 and update generated files.
- Update build system and documentation to support now directory variables
  offered by Autoconf 2.61.
- Replace usages of PGAC_CHECK_ALIGNOF by AC_CHECK_ALIGNOF, now available
  in Autoconf 2.61.
- Drop our patched version of AC_C_INLINE, as Autoconf now has the change.

  http://archives.postgresql.org/pgsql-hackers/2007-10/msg01470.php

Brendan Jurd

Minor rearrangements to make a few tests in a more logical order.

Olivier Prenant, fixed by Peter.

code relies on the checking macro actually being called at the end, or the
automatic undiversion will produce garbage.  These sort of implicit
side-effects undermine the modularity of the macros and happen to break the
ODBC driver which makes use of them.

Also put the warnings at the very end of configure, so there is an even
better chance of seeing them.

Also cut back on excessive use of *** to decorate configure error messages.
If it's an error message, you are sure to see it without any decoration.

and neither is "|" or "\|" in basic regular expressions.

Martijn van Oosterhout

in port/pg_config_paths.h.

   --with-libedit-preferred  prefer BSD Libedit over GNU Readline

Marko Kreen