pgsql: Prevent Perl from introducing a possibly-incompatible definition

Log Message:
-----------
Prevent Perl from introducing a possibly-incompatible definition of type
"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.

Tags:
----
REL8_1_STABLE

Modified Files:
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pgsql/src/pl/plperl:
plperl.c (r1.94.2.6 -> r1.94.2.7)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/plperl.c?r1=1.94.2.6&r2=1.94.2.7)
spi_internal.h (r1.7 -> r1.7.2.1)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/spi_internal.h?r1=1.7&r2=1.7.2.1)