-Edit- I couldnt wait till morning, I'm using stormc!! thanks anyway people.
Just in case you or someone else is interested: where is the libauto.a? The trick with gcc is that the names of the libraries don't match the way you call them (libamiga.a is -lamiga etc)
I had the same errors when switching from stormc to gcc, and -lauto solved the undefined references. For the type conversion, I remember that's because stormc is doing some of the work and with gcc you've got to be more explicit (check the autodocs or other sources compilable with gcc).
In the end I succeeded compiling reaction with gcc.
