hello people!

just trying to use extconf.rb script using mkmf to compile a bundle for 
osx (some c++ libraries)

compilation is going ok and linking (even libstdc++) seems ok, but 
invoking the shared bundle in IRB gives me:

dyld: ruby Undefined symbols:
<snip>
(long list of symbols)

could someone point at the most common reason this happens?

sorry for such n00b question, but just can't figure it out, tried 
several different LDFLAGS options after googling, and currently have 
the following options set:

if RUBY_PLATFORM =~ /darwin/
     $CPPFLAGS += " -DUNIX"
     $LDFLAGS += " -lstdc++ -L/usr/local/lib"
     dir_config("fmod","/usr/local/include","/usr/local/lib")
end

if have_header("fmod.h")
     if RUBY_PLATFORM =~ /darwin/
         CONFIG["CC"] = "c++"
         CONFIG["LDSHARED"].gsub!("cc","g++") #make sure you're using 
g++ so it links libstdc++
         CONFIG['LDSHARED'].gsub!('gcc','g++')
         $create = true if have_library("fmod")
     elsif have_library("fmod") #more than likely a linux box
         CONFIG['LDSHARED'].gsub!('gcc','g++') #make sure c++ gets 
linked properly
         $create = true
     end
end

any advice?

thanks!

david casal