DIP45: fixing the dllimport/dllexport issue

[Benjamin Thaut]

The current behaviour of export is not sufficient to create a shared 
runtime on windows. Its alos not working very well in a few other cases. 
For background information please read the links provided in the DIP. 
This DIP tries to solve the problem by imitating the proven preprocessor 
techniques used in C/C++ to create windows dlls.

Destroy.
Kind Regards
Benjamin Thaut