busybox

env: -u option fails due to typo

The -u option is supposed to be allowed to appear multiple times; the
option string supplied to getopt32long requires it to be followed by a
nonnegative integer.

Reported-by: Keith Maxwell <keith.maxwell@gmail.com>
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>