That's probably a heck of a lot more difficult than just running a s390x container via QEMU user mode emulation.

Even regardless of difficulty, building and running on real hardware is desirable to make sure that you've actually got a correct build going. Emulators can have bugs, including bugs that might give you a false positive about working builds when it really isn't.

Emulation is never perfect and, if you are running your database on a “seven nines” platform, you really want it thoroughly tested on the real thing.

Besides, it’s much faster to build on real metal than on Hercules or QEMU.

It is under the Q Public License. Had to look it up because it has been a while Qt used it.