Due to the new and tighter intregration in ruby 1.9 with rubygems it is no longer possible to install ruby 1.9 without also installing rubygems. $ ruby19 /usr/lib64/ruby/1.9.1/rubygems.rb:30:in `require': cannot load such file -- rubygems/defaults (LoadError) from /usr/lib64/ruby/1.9.1/rubygems.rb:30:in `<top (required)>' from <internal:gem_prelude>:1:in `require' from <internal:gem_prelude>:1:in `<compiled>' Most likely we need to PDEPEND on virtual/rubygems in this case, but this needs testing to make sure this also works when bootstrapping.
Fixed in ruby-1.9.3_p194-r1 by adding a PDEPEND on dev-ruby/rubygems.