busybox

hush: propagate (output,n) parameters into expand_one_var()

This is necessary since expand_one_var() for ${var:+ARG} must create more than one
output word, and thus can't simply return a char*.

function                                             old     new   delta
expand_one_var                                      1610    1643     +33
expand_vars_to_list                                 1139    1125     -14
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(add/remove: 0/0 grow/shrink: 1/1 up/down: 33/-14)             Total: 19 bytes

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