I've only noticed it due to delegates entry for svg being incorrect. The problem here is that ImageMagick actually uses those modules la files, so removing them results in an incorrect tree. When those files are missing, ImageMagick falls back to using entries in /usr/$(libdir)/${P}/config/delegates.xml, so in most cases it seems to work, but that makes building all those modules redundant. I think that a better solution would be changing find "${D}"/usr/$(get_libdir) -name '*.la' -delete to: find "${D}"/usr/$(get_libdir) -name '*.la' -exec sed -i -e \ 's:^dependency_libs=.*$:dependency_libs='\'\'':' '{}' \; || die rm "${D}"/usr/$(get_libdir)/libMagick*.la This leaves the needed la files, but they won't be popping up in revdep-rebuild anymore and the modules will still be used.
actually, 6.5.9.4 isn't in portage anymore, and the .la files are restored in -r1, but your solution looks intresting... we might want to incorporate it, so leaving open
nah, let's not put that in ebuilds, doesn't look very sustainable as this should be a eclass function or embedded in ones functionality instead.