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.

src/pl/plperl/plperl.c

@@ -33,7 +33,7 @@
  *	  ENHANCEMENTS, OR MODIFICATIONS.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.94.2.6 2007/06/28 17:50:17 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.94.2.7 2007/11/22 17:47:40 tgl Exp $
  *
  **********************************************************************/
 
@@ -76,6 +76,11 @@
 #define pTHX void
 #endif
 
+/* perl may have a different width of "bool", don't buy it */
+#ifdef bool
+#undef bool
+#endif
+
 
 /**********************************************************************
  * The information we cache about loaded procedures

src/pl/plperl/spi_internal.h

@@ -3,6 +3,11 @@
 #include "XSUB.h"
 #include "ppport.h"
 
+/* perl may have a different width of "bool", don't buy it */
+#ifdef bool
+#undef bool
+#endif
+
 int			spi_DEBUG(void);
 
 int			spi_LOG(void);