$ bin/rbx -P gem --backtrace install rails
ERROR:  While executing gem ... (RuntimeError)
    Explain why you did this: email ephoenix@engineyard.com
	/home/pierre/Source/Ruby/rubinius/lib/zlib.rb:1444:in `do_checksum'
	/home/pierre/Source/Ruby/rubinius/lib/zlib.rb:1435:in `crc32'
	/home/pierre/Source/Ruby/rubinius/lib/zlib.rb:1028:in `read'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems.rb:405:in `gunzip'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/remote_fetcher.rb:150:in `fetch_path'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/spec_fetcher.rb:197:in `load_specs'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/spec_fetcher.rb:175:in `list'
	kernel/common/array.rb:580:in `each'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/spec_fetcher.rb:165:in `list'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/spec_fetcher.rb:116:in `find_matching'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/spec_fetcher.rb:69:in `fetch'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/dependency_installer.rb:103:in `find_gems_with_sources'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/dependency_installer.rb:189:in `find_spec_by_name_and_version'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/dependency_installer.rb:211:in `install'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/commands/install_command.rb:100:in `execute'
	kernel/common/array.rb:580:in `each'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/commands/install_command.rb:84:in `execute'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/command.rb:137:in `invoke'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/command_manager.rb:105:in `process_args'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/command_manager.rb:78:in `run'
	/home/pierre/Source/Ruby/rubinius/lib/rubygems/gem_runner.rb:39:in `run'
	/home/pierre/Source/Ruby/rubinius/lib/bin/gem.rb:24
	kernel/common/compiled_method.rb:253:in `activate_as_script'
	kernel/common/compiled_method.rb:246:in `as_script'
	kernel/common/compile.rb:241:in `single_load'
	kernel/common/compile.rb:103:in `unified_load'
	kernel/common/compile.rb:397:in `load'
	kernel/loader.rb:222