Can I use Qwt with Microsoft compiler or not?

[Uwe]

What should be in qwtconfig.pri? "CONFIG += QwtDll" or "#CONFIG += QwtDll"? or no difference?

qwtconfig.pri is for building Qwt itself, not for building an application using Qwt.

Almost everything above shows that you didn't read: http://qwt.sourceforge.net/qwtinstall.html.

Uwe