busybox

udhcpd: clamp down huge auto_times to ~2M seconds, better EINTR poll handling

EINTR _should_ only happen on two signals we trap, and safe_poll
_should_ work here just fine, but there were kernel bugs where spurious EINTRs
happen (e.g. on ptrace attach). Be safe.

function                                             old     new   delta
udhcpd_main                                         1437    1468     +31

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>