rb-gslとRailsは同時に使えない？

開発 Rails

GSLのRubyバインディング、rb-gslとRails、と言うかRubyGemsを同時に使おうとすると落ちる。こんな感じ。

$ irb
irb(main):001:0> require 'gsl'
=> true
irb(main):002:0> require 'rubygems'
TypeError: superclass mismatch for class Rational
        from /opt/local/lib/ruby/1.8/rational.rb:64
        from /opt/local/lib/ruby/1.8/date.rb:196:in `require'
        from /opt/local/lib/ruby/1.8/date.rb:196
        from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:2:in `require'
        from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:2
        from /opt/local/lib/ruby/1.8/yaml.rb:392:in `require'
        from /opt/local/lib/ruby/1.8/yaml.rb:392
        from /opt/local/lib/ruby/site_ruby/1.8/rubygems/remote_fetcher.rb:3:in `require'
        from /opt/local/lib/ruby/site_ruby/1.8/rubygems/remote_fetcher.rb:3
        from /opt/local/lib/ruby/site_ruby/1.8/rubygems/source_index.rb:8:in `require'
        from /opt/local/lib/ruby/site_ruby/1.8/rubygems/source_index.rb:8
        from /opt/local/lib/ruby/site_ruby/1.8/rubygems.rb:504:in `require'
        from /opt/local/lib/ruby/site_ruby/1.8/rubygems.rb:504
        from (irb):2:in `require'
        from (irb):2
irb(main):003:0>

既存のクラスをrb-gslが触って、そのせいでrubygemsがこけるように見える。