Comment 1 for bug 663156

You don't need to set CROSS_COMPILE to cross-build the kernel; the kernel rules have been fixed to set CROSS_COMPILE to the host triplet (unless it's already set). This might be a natty-only fix though.

I think we should avoid package-specific workaround as much as we can, and since kernel cross builds should be supported fine here, I'd rather we do not add this environment variable feature unless there is a strict need for it.