When i want to compile seq24 0.9.0 from official portage tree, i have error with gtk. I found a patch from internet, i applied this patch and it works now.
The ebuild : # Copyright 1999-2009 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2 # $Header: /var/cvsroot/gentoo-x86/media-sound/seq24/seq24-0.9.0.ebuild,v 1.5 2009/08/01 06:37:56 ssuominen Exp $