Add MSVC builtin macros to setuphelpers

[Vlas Puhov]

Hi!

That's great news!!!

   The only thing I don't understand is: why are those macros enabled only if 
_MSC_VER is defined??? What about winebuild/mingw compilers? They let you build 
windows apps even on Linux machine. So I can build .exe files very easily, but 
kdevelop complains that __stdcall is not defined :( That's really 
disappointing...
   So, wouldn't it be better if those macros could be configured at run-time 
instead of compile-time?  E.g. through some configuration page where you could 
choose appropriate compiler? Or shouldn't they be defined globally for all 
compilers?