I'm afraid libMyStuff.def is a bit too Unix-like, I *think* it's a lot more common in the Windows universe to have it called MyStuff.def. But I don't know exactly if people even know what a .def file is these days :), and I have little knowledge how folks are naming their .def files, so ...
Usually with the same name as the dll is the least confusing (as in MyStuff.dll and MyStuff.def). We for sure still use it (on Windows) but I don't know for wine/lib.
bye Fabi