> Yup, turned out patching GCC was too difficult. I'm experimenting a
> filter over inputs passed to set-path-environment-variable in set-paths.

This is also quite tricky, because the "libc" input passed to set-paths
must not be removed from C_INCLUDE_PATH in (gnu packages commencement)
for mes packages.

So, maybe the best option is to patch QEMU directly, as proposed in
the attached patch. WDYT?

Thanks,

Mathieu