Building a DLL with GCC/G++

I have a MingW (Dev-C++) project which builds fine as a .EXE, but if i build it as a DLL there is an error at the very last step of the linkage, dlltool builds a corrupted dll and it does not even generate a .def file. This should be a problem with my environment that i am not sure how to fix, and i think switching to Visual Studio is not an option because the linked static libraries have been built with GCC so they are incompatible with MSVC linker. If you are familiar with GCC and/or MingW/DevC++, please compile correctly the DLL for me and then provide me with the tools and command lines you used to build it, so i can do it myself when i update my source code. If you manage to do it with Visual Studio, it is fine for me too, although it's unlikely to happen. Give me info on how you managed to do it. I have attached a little .zip archive with all the source and libraries required.