I tried to create a correct import library out of the DLLs using the tool dlltool, but am unsuccesdful. I keep getting errors like undefined reference to `WGSetPlotArea@44' The problem lies in the decoration: I do not know how to get rid of the @44, or how to adapt my code to take it into account.
After a lot of trial and even more error, I managed to get it working. I was able to create a new import library, which I can use to link with, without modification of the header files.