ash: allow "trap NUM [SIG]..." syntax

While at it, make get_signum() return -1 for numeric strings >= NSIG.

function                                             old     new   delta
trapcmd                                              292     306     +14
get_signum                                           295     300      +5
builtin_trap                                         413     412      -1
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(add/remove: 0/0 grow/shrink: 2/1 up/down: 19/-1)              Total: 18 bytes

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