title: Building gem throws IOError
body: <p>Trying to build a gem like so.</p>
  
  <pre><code>gem build my-awesome-theme.gemspec
  </code></pre>
  
  <p>And for some unknown reason it's throwing the following error.</p>
  
  <pre><code>/Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/package/tar_writer.rb:249:in `write': closed stream (IOError)
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/package/tar_writer.rb:249:in `close'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/package/tar_writer.rb:87:in `ensure in new'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/package/tar_writer.rb:87:in `new'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/package.rb:231:in `block in build'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/package.rb:230:in `open'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/package.rb:230:in `build'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/package.rb:111:in `build'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/commands/build_command.rb:48:in `execute'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/command.rb:305:in `invoke_with_build_args'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/command_manager.rb:167:in `process_args'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/command_manager.rb:137:in `run'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/gem_runner.rb:54:in `run'
  from /Users/robertrawlins/.rvm/rubies/ruby-2.3.1/bin/gem:21:in `&lt;main&gt;'
  </code></pre>
  
  <p>Have tried complete rebuild of the ruby environment using RVM, and fresh clone of the gem source from GitHub but the problem persists.</p>
  
  <p>Running Mac OSX, RVM and Ruby 2.3.1</p>
  
  <p>Any help greatly received. :)</p>