Fix compilation against perl 5.8.x
Fix compilation against perl 5.8.x

The POSIX module included with perl 5.8.x apparently did not setup
prototypes for the various numerical min/max constants, at least when
you specified an export list that does not include these constants.  Fix
by adding parens.

potyl/perl-Glib,potyl/perl-Glib,potyl/perl-Glib