title: Alternative to 'ruby-debug19' (culprit 'linecache19') on ruby 2.0.0p247?
body: <p>I am frustrated because I have tried other StackOverflow articles on this issue, but have been unsuccessful in fixing my own error. When I call</p>
  
  <pre><code>'gem install linecache19'
  </code></pre>
  
  <p>...the following error is outputed</p>
  
  <pre><code>ERROR:  Error installing linecache19:
      ERROR: Failed to build gem native extension.
  
      /home/user/.rvm/rubies/ruby-2.0.0-p247/bin/ruby extconf.rb
  checking for vm_core.h... no
  /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/ruby_core_source.rb:39:in `create_makefile_with_core': Use RbConfig instead of obsolete and deprecated Config.
  /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/ruby_core_source.rb:39:in `create_makefile_with_core': Use RbConfig instead of obsolete and deprecated Config.
  checking for vm_core.h... no
  *** extconf.rb failed ***
  Could not create Makefile due to some reason, probably lack of necessary
  libraries and/or headers.  Check the mkmf.log file for more details.  You may
  need configuration options.
  
  Provided configuration options:
      --with-opt-dir
      --without-opt-dir
      --with-opt-include
      --without-opt-include=${opt-dir}/include
      --with-opt-lib
      --without-opt-lib=${opt-dir}/lib
      --with-make-prog
      --without-make-prog
      --srcdir=.
      --curdir
      --ruby=/home/user/.rvm/rubies/ruby-2.0.0-p247/bin/ruby
      --with-ruby-dir
      --without-ruby-dir
      --with-ruby-include
      --without-ruby-include=${ruby-dir}/include
      --with-ruby-lib
      --without-ruby-lib=${ruby-dir}/
  /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/contrib/uri_ext.rb:268:in `block (2 levels) in read': Looking for http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-2.0.0-p247.tar.gz and all I got was a 404! (URI::NotFoundError)
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1413:in `block (2 levels) in transport_request'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http/response.rb:162:in `reading_body'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1412:in `block in transport_request'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1403:in `catch'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1403:in `transport_request'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1376:in `request'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1369:in `block in request'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:852:in `start'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1367:in `request'
      from /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/contrib/uri_ext.rb:239:in `block in read'
      from /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/contrib/uri_ext.rb:286:in `connect'
      from /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/contrib/uri_ext.rb:234:in `read'
      from /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/contrib/uri_ext.rb:128:in `download'
      from /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/ruby_core_source.rb:55:in `block in create_makefile_with_core'
      from /home/user/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/tempfile.rb:324:in `open'
      from /home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/ruby_core_source.rb:51:in `create_makefile_with_core'
      from extconf.rb:19:in `&lt;main&gt;'
  Requesting http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-2.0.0-p247.tar.gz
  
  
  Gem files will remain installed in /home/user/.rvm/gems/ruby-2.0.0-p247/gems/linecache19-0.5.12 for inspection.
  Results logged to /home/user/.rvm/gems/ruby-2.0.0-p247/gems/linecache19-0.5.12/ext/trace_nums/gem_make.out
  </code></pre>
  
  <p>Please notice the culprit line...</p>
  
  <pre><code>/home/user/.rvm/gems/ruby-2.0.0-p247/gems/ruby_core_source-0.1.5/lib/contrib/uri_ext.rb:268:in `block (2 levels) in read': Looking for http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-2.0.0-p247.tar.gz and all I got was a 404! (URI::NotFoundError)
  </code></pre>
  
  <p>Obviously this does not work...the url <a href="http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-2.0.0-p247.tar.gz" rel="nofollow">http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-2.0.0-p247.tar.gz</a> doesn't make sense. (Accesses Ruby1.9 then looks for the Ruby2.0 tar.gz)</p>
  
  <p>This is for a class project (for CS169: Software Engineering at UC Berkeley) that requires the gem 'ruby-debug19', which tries to install 'linecache19'.</p>
  
  <p><strong>Do I have to downgrade to ruby1.9, or can I keep using ruby2.0?</strong></p>
  
  <p>When I call</p>
  
  <pre><code>$ruby -v
  </code></pre>
  
  <p>I get the following...</p>
  
  <pre><code>ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-linux]
  </code></pre>
  
  <p>I am using RVM.</p>
  
  <p>I am slightly suspicious that linecache19 does not support ruby 2.0.</p>