title: Missing functions in ruby 1.8
body: <p>I have a ruby gem that I developed with ruby 1.9, and it works. With ruby 1.8, though, it says this when I try to run it:</p>
  
  <pre><code>dyld: lazy symbol binding failed: Symbol not found: _RBIGNUM_SIGN
    Referenced from: /Users/Adrian/Desktop/num_to_bytes/ext/num_to_bytes/num_to_bytes.bundle
    Expected in: flat namespace
  
  dyld: Symbol not found: _RBIGNUM_SIGN
    Referenced from: /Users/Adrian/Desktop/num_to_bytes/ext/num_to_bytes/num_to_bytes.bundle
    Expected in: flat namespace
  
  Trace/BPT trap
  </code></pre>
  
  <p>If I comment out the line that uses <code>RBIGNUM_SIGN</code>, it complains about other functions like <code>rb_big_modulo</code>. Some things work, like <code>NUM2LONG</code>. Here are some things I have tried:</p>
  
  <ul>
  <li>In <a href="http://github.com/ruby/ruby/blob/ruby_1_8_7/ruby.h" rel="nofollow noreferrer">http://github.com/ruby/ruby/blob/ruby_1_8_7/ruby.h</a>, <code>RBIGNUM_SIGN</code> is defined. But in all versions of ruby I have tried, it is not there.</li>
  <li>I guessed that maybe it was defined in a different .h file. Knowing that Hpricot works with 1.8, I looked at <a href="http://github.com/hpricot/hpricot/blob/master/ext/hpricot_scan/hpricot_scan.h" rel="nofollow noreferrer">http://github.com/hpricot/hpricot/blob/master/ext/hpricot_scan/hpricot_scan.h</a>. It doesn't include any other files that #define it.</li>
  <li>Putting things like <code>extern VALUE rb_big_modulo(VALUE x);</code> at the beginning of my extension don't help.</li>
  <li>Using a brand new Ubuntu installation, I <code>apt-get</code>ted ruby, tried to install the gem, and it didn't work either.</li>
  <li>Putting <code>have_library 'ruby', 'rb_big_modulo'</code> in my extconf.rb didn't work.</li>
  </ul>
  
  <p>As you can probably see, I am getting desperate (after weeks of trying things!). So, how can I get this to work?</p>
  
  <p>Here is the gem: <a href="http://rubygems.org/gems/num_to_bytes" rel="nofollow noreferrer">http://rubygems.org/gems/num_to_bytes</a></p>
  
  <p>Here is the source: <a href="http://gist.github.com/404584" rel="nofollow noreferrer">http://gist.github.com/404584</a></p>