ftp://ftp.imagemagick.org/pub/ImageMagick/delegates/libfpx-1.2.0.9.tar.bz2 should either be an optional dependency of imagemagick, or should be isntalled as part of the imagemagick ebuild. similarly, jpeg2000 support should be a dependency. jasper looks like the prefered choice for jp2 support. and on that subject, hdf5 is already in portage, so that ought to be an optional dependency of imagemagick as well, enabling --with-hdf.
please submit your changes (patches, ebuilds)
Please see Bug#35358 for a jasper ebuild and Bug#35359 for a libfpx ebuild
Commited to CVS.