On macosx, my usual approach with opensource projects is (in this order):

1. Use binary distribution or installation procedure from the project site. For your problem: Re: Gtk2 installation on OS X fails
2. If there is nothing for macosx on the project site, I use the Macports package http://www.macports.org/install.php (check the freshness of the package)
3. Finally, I try to compile (or use cpan...) myself and I fail :-)