quote_literal, quote_nullable, quote_ident,
    encode_bytea, decode_bytea, looks_like_number,
    encode_array_literal, encode_array_constructor.
Split SPI.xs into two - SPI.xs now contains only SPI functions. Remainder
are in new Util.xs.
Some more code and documentation cleanup along the way, as well as
adding some CVS markers to files missing them.

Original patch from Tim Bunce, with a little editing from me.

"bool" into plperl.c.  This has always been a hazard since Perl allows a
platform-specific choice to define bool as int rather than char, but
evidently this didn't happen on any platform we support ... until OS X 10.5.
Per report from Brandon Maust.

Back-patch as far as 8.0 --- a bit arbitrary, but it seems unlikely anyone
will be trying to port 7.x onto new platforms.

back-stamped for this.

Prepared queries for PLPerl, plus fixing a small plperl memory leak. Patch
and docs from Dmitry Karasik, slightly editorialised.

Rationalise perl header inclusions via a common include file, which also
declares routines in plperl.c and spi_internal.c used in other files.

Along the way, also stop perl from hijacking stdio and other stuff on Windows.