This is fix patch for ebuild of ruby with cjk USE flag. When CJK USE flag is used ruby is compilied with oniguruma that is new regexpression engine for ruby 1.9. But Oniguruma version set in ebuild is old and it seems oniguruma-2.3.1-gentoo.patch is needless. Oniguruma's author said that patch could allow some problem when it processes huge regular expression. Actually the ruby installed by ebuild in Portage tree makes some problem for another package install(this is docdiff, it has not been in Portage tree yet.) And this patch can be applied to previous version.(ruby-1.8.4-r1.ebuid)
Created attachment 83299 [details, diff] patch for Ruby-1.8.4-r2.ebuild
patched - thanks for the report.