Comment 2 for bug 1960592

Hi,
I think this is actually a known non-issue.

Your command is equal to:
  $ sudo apt build-dep qemu

That is you asking for the complete build dependencies of qemu, which include some bits that need to be cross compiled for various architectures. That is what adds the dependencies to all the gcc-$arch cross compilation packages which are not available on ppc64 systems.

But - if you do not want to build "all of qemu" and instead are just interested to build qemu on ppc64 - you can tell apt that this is what you want.

From the man page:
--arch-only
  Only process architecture-dependent build-dependencies.

So with the following you most likely get what you actually wanted (and it works on ppc64):
  $ sudo apt --arch-only build-dep qemu

If I'm wrong and you did want to build not only the ppc64 but also the arch independent binaries in ppc64, then this bug would actually be a feature request to the cross toolchain to be available on more architectures.

Either way as I see it right now it does not seem to be a mistake in qemu, but you can let us know once you had time to read this.