You mean link it with winelib when compiling, or build a .so library you link in at runtime?
I mean creating what wine calls a winelib app: it uses wine magic for startup (it ends up being a .so file run by the wine loader, and not a full native ELF application).
By the way, how essential is STI.DLL for getting a scanner driver to work, and can you use the one provided with Windows?
Dunno. As any DLL (especially the ones without hardware relationship) should be run in Wine, but YMMV (depending on the dependencies of the said DLL).
A+