Running a CMake/Ninja build makes QtCreator unresponsive

When building a relatively large CMake project with Ninja, Ninja hogs the entire CPU and the whole system becomes unresponsive. That's not the fault of QtCreator, but it's inconvenient. I wonder if there is anything that QtCreator could do when invoking Ninja, for instance decreasing the process priority of the build in order to improve the user experience.

This does not happen when building Qbs projects btw.