While running cmake to build a target qDebug() output is not shown from a custom build tool

We use custom build tools to generate for e.g. our database.

The database is build for example with a cm command (e.g. cm test_db),

while building the target no output from the custom tool (using qDebug/qWarning) is show on the "Compile output" window.

The reason for this is, that the Qt Message handler forwards the output to "OutputDebugString" if no console could be acquired and in this case QtCreator doesn't show this output, which it does if you run or debug an application.

Overriding this behavior with the environment variable 

QT_ASSUME_STDERR_HAS_CONSOLE=1

does show the outpout for the cmake case, but then no output is shown while debugging the application.

I think QtCreator should also output string send to OutputDebugString on the "Compile Output" Window.