* in some cases (e.g. with external toolchain which doesn't respect our
reasonably old version set in OLDEST_KERNEL) it's possible to have libc
which requires newer kernel than what we have on builders, qemu supports
-r param to use different uname than what's returned by host system.
* change qemu_run_binary to pass -r ${OLDEST_KERNEL} and add the same to
QEMU_OPTIONS which are used by qemuwrapper-cross
* maybe we should eventually convert all qemu_run_binary usages always include
qemuwrapper-cross dependency and always call qemu through that (it
seems very strange that qemu_target_binary is called from qemuwrapper
and for allarch recipes it can return qemu-allarch as qemu binary).
