Ruby hangs when trying to install RubyGems

I've just set up a minimal Gentoo install and emerged Ruby 1.8.5 from portage. I then went to emerge rubygems, and found that it hangs. Manually downloading the file and running 'ruby setup.rb' also hangs. The following are the last few lines I get before nothing happens, and my CPU sits at 100% (from Ruby):

Successfully built RubyGem Name: sources Version: 0.0.1 File: sources-0.0.1.gem

Any help would be great.

A compilation from source makes no difference, either. Is this some sort of unique Gentoo issue?

I had the same problem both with emerging rubygems or directly running setup.rb from rubygems-0.9.2.tgz I fixed it by patching rubygems-0.9.2/lib/rubygems/packages.rb:

450,453c450,453 < if @io.respond_to? :seek < # avoid reading... < @io.seek(size - entry.bytes_read, IO::SEEK_CUR) < else