Qt Multimedia is not built correctly on MingW

We are not detecting WMF when building with MingW and thus building QtMM without any backend. This leads e.g. to the following:

On a fresh Windows 10 (21H1) installation the "Media Player Example" crashes immediately after launch.

I used the Qt 6.2 (Beta3) binaries from the online installer.

To create the executable I did use "Qt Creator 4.15.2" with the automatically generated Kit "Desktop Qt 6.2.0 MinGW 64-bit". The compiler was "MinGW 8.1.0 64-bit".

Playback of media files with the Windows Media Player did work.

Additional information:

Line 71 in the file "player.cpp" causes a "segmentation fault":

m_audioOutput = new QAudioOutput(this);

The last function call before the crash was:

QDummyIntegration::devices