RVM を使用して ruby 2.2.3 をインストールしました。正常にインストールされましたが、gem install rails (またはその他の gem) を実行すると、次のエラーが表示されます。
$ gem install rails
/home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- win32/resolv (LoadError)
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:964:in `default_config_hash'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:982:in `block in lazy_initialize'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:975:in `synchronize'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:975:in `lazy_initialize'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:357:in `block in lazy_initialize'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:355:in `synchronize'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:355:in `lazy_initialize'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:515:in `fetch_resource'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:509:in `each_resource'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/resolv.rb:490:in `getresource'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/remote_fetcher.rb:92:in `api_endpoint'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/source.rb:46:in `api_uri'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/source.rb:85:in `dependency_resolver_set'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/resolver/best_set.rb:23:in `block in pick_sets'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/source_list.rb:97:in `each'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/source_list.rb:97:in `each_source'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/resolver/best_set.rb:22:in `pick_sets'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/resolver/best_set.rb:28:in `find_all'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/resolver/installer_set.rb:151:in `find_all'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/resolver/installer_set.rb:54:in `add_always_install'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/dependency_installer.rb:473:in `resolve_dependencies'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/commands/install_command.rb:238:in `install_gem'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/commands/install_command.rb:299:in `block in install_gems'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/commands/install_command.rb:295:in `each'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/commands/install_command.rb:295:in `install_gems'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/commands/install_command.rb:202:in `execute'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/command.rb:307:in `invoke_with_build_args'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/command_manager.rb:168:in `process_args'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/command_manager.rb:138:in `run'
from /home/laury/.rvm/rubies/ruby-2.2.3/lib/ruby/site_ruby/2.2.0/rubygems/gem_runner.rb:54:in `run'
from /home/laury/.rvm/rubies/ruby-2.2.3/bin/gem:21:in `<main>'
Windows 10 Pro、Cygwin、rvm 1.27.0 を使用しています。RVM の github ( https://github.com/rvm/rvm/issues/3519 ) には、私が得ているものとかなり似ている古い未解決の問題がありましたが、答えは見つかりませんでした。