MITK does support parallel compilation and we're making heavy use of it. What makes you believe, that we don't?

@kislinsk I used to run ninja on Linux without -j1 and it used all my cores as parallel jobs, it fails with errors, I can try to reproduce to provide log for research, maybe issue was different

I cannot say anything about ninja as we don't officially support it, but make -j[n] works great.

@kislinsk yes, seems like it was all Eigen and ninja (another issue) related (I just used to understand issue wrong first time), with Eigen fix is applied everything is going fine.