How do I add my tcg tests to check-tcg?

[Bastian Koppelmann]

Hi Alex,

I have some time again to integrate my tcg tests patch for TriCore [1]. However,
I'm struggeling a bit to get through the details of the Makefiles. I'm assuming
the right rule to run is 'make check-tcg'. I tried running that for
xtensa-softmmu, arm-softmmu, and aarch64-softmmu, but they are always skipped.
Digging into the Makefiles I found that there is some way to use the dockerfiles
to run the test. Can someone elighten me on how to properly use this?

Thanks and cheers,
Bastian

[1] https://lists.nongnu.org/archive/html/qemu-devel/2018-05/msg00074.html