Missing features in ruby ​​1.8

I have a ruby ​​stone that I developed with ruby ​​1.9 and it works. However, with ruby ​​1.8, this says it when I try to run it:

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

      

        
        
        
      

    

If I comment out the line using RBIGNUM_SIGN

it complains about other features like rb_big_modulo

. Some things work, for example NUM2LONG

. Here are some things I've tried:

• In http://github.com/ruby/ruby/blob/ruby_1_8_7/ruby.h , RBIGNUM_SIGN
  
  . But in all versions of the ruby ​​I have tried, it is not there.
• I guessed that it might have been defined in another .h file. Knowing that Hpricot works with 1.8, I looked at http://github.com/hpricot/hpricot/blob/master/ext/hpricot_scan/hpricot_scan.h . It does not contain any other files that are #define.
• Putting things like extern VALUE rb_big_modulo(VALUE x);
  
  at the beginning of my expansion doesn't help.
• Using a fresh Ubuntu install, I apt-get
  
  ted ruby ​​tried to install the gem and it didn't work either.
• The tab have_library 'ruby', 'rb_big_modulo'
  
  in my extconf.rb is not working.

As you can probably see, I am desperate (after weeks of trying!). So how can I get this to work?

Here's a gem: http://rubygems.org/gems/num_to_bytes

Here is the source: http://gist.github.com/404584