GIMP install doesn't see GTK

[Shrp]

I'm running ./configure while installing the latest version of GIMP on a
Solaris 2.8 machine, and it doesn't see the version of Perl-Gtk that I have
installed already. What link, path modification, or file tweak do I need to
do to get it to see what I've already installed? Also, there seems to be a
possibility that it's looking at an old version of GTK that I don't know how
to (properly) get rid of.

I have Gtk installed in /opt/gtk+-1.2.9

Thanks!

% ./configure
...
checking for PDL support... yes
checking for PDL include path... -I/opt/perl-5.8.0/lib/site_perl/5.8.0/sun4-solaris/PDL/Core
checking for PDL typemap... /opt/perl-5.8.0/lib/site_perl/5.8.0/sun4-solaris/PDL/Core/typemap.pdl

NOTICE: unable to use the Perl-Gtk interface. Many features (like
Gimp::Fu) rely on this extension. You can build without it (and
many scripts will be disabled or run with reduced functionality
only), but it's better to install it (version 0.6123 or higher is
required, you can get it from ftp://ftp.gimp.org/pub/gtk/perl/ or
any CPAN mirror.


NOTICE: Parse::RecDescent not found, scm2perl, the Scheme->Perl
translator, will not work. This is normally not a problem, since
it is quite unimportant for most people.

building embedded perl module... no
writing Gimp/Config.pm... ok
Warning: prerequisite Parse::RecDescent 1.6 not found.
Writing Makefile for Gimp::Lib
Writing Makefile for Gimp::Net
Note (probably harmless): No library found for -lgimp
Note (probably harmless): No library found for -lgimpui
Writing Makefile for Gimp::UI
Writing Makefile for Gimp
%