pgsql: Update ppport.h to not cause warnings with newest Perl versions.

Log Message:
-----------
Update ppport.h to not cause warnings with newest Perl versions.
This is just the minimal necessary change; we might want to adopt
later PPPort output instead.

Modified Files:
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pgsql/src/pl/plperl:
ppport.h (r1.10 -> r1.11)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/ppport.h.diff?r1=1.10&r2=1.11)