Luis Lavena wrote:
> What you can try to do is use the extconf process to create you the
> needed defines.
> 
> http://github.com/datamapper/do/blob/master/do_mysql/ext/do_mysql/extconf.rb#L77-79
> 
> HTH,

Thank you, Luis! That helped me a lot, I now solved the problem by 
adding this to my extconf.rb:
---------------------------------
print("Checking whether we are running Ruby 1.9... ")
if RUBY_VERSION >= "1.9.0"
  $CFLAGS << " -DUSING_RUBY_19"
  puts "yes"
else
  puts "no"
end
---------------------------------
And in the C code I check wheather USING_RUBY_19 is defined.

Thank you!
Marvin
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