Have a parallel generator step for Multi-Config setups
I was thinking at setting Ninja Multi-Config
as default Generator for Qt Creator (https://codereview.qt-project.org/c/qt-creator/qt-creator/+/520205), but then noticed that the Generating done
time increased.
This is time is now proportional with the entries in the CMAKE_CONFIGURATION_TYPE
variable.
The advantages of not having to run the configure step for every build step would go away if for every cmake run the generating time has multiplied by a factor of 3 (or 4).
If the generator step is doing parallel work, then it shouldn't take longer than a single configuration!