Comment 4 for bug 715429

> Why can't ccache be an environment variable like CROSS_COMPILE? If set, we use it.

I think this is because the usual way to use ccache is to have a symlink to ccache with the name of your compiler under /usr/lib/ccache, and prepend that dir to PATH, but there is no such link for the cross-toolchain. This is bug #605189; let's not get distracted here.

> the kallsyms is indeed a amd64 binary on my system.

Ok; that's wrong then. Is this binary needed in the package at all? (On any architecture)
If not, we should fix the kernel packaging or upstream rules to not install it.

if it's needed in the package, we should fix the build to produce an ARM one and install that one (maybe the build needs to produce a x86 one as well for the time of the build).