qmake: Test for current spec.

Question

I would like to detect whether qmake is currently building using MingW (win32-gcc) or Visual Studio (win32-msvc200X).

At the moment I am using the following construct:

windows{
    contains(QMAKE_CC, gcc){
        # MingW
    }
    contains(QMAKE_CC, cl){
        # Visual Studio
    }
}

This does not seem particularly robust. Is there a better way?