ash: 'nolog' and 'debug' options cause "$-" to wreak havoc

ash: 'nolog' and 'debug' options cause "$-" to wreak havoc

Upstream commit:

    Date:   Tue Mar 6 17:40:37 2018 +0000
    expand: 'nolog' and 'debug' options cause "$-" to wreak havoc

    Op 29-03-17 om 20:02 schreef Martijn Dekker:
    > Bug: if either the 'nolog' or the 'debug' option is set, trying to
    > expand "$-" silently aborts parsing of an entire argument.
    >
    > $ dash -o nolog -c 'set -fuC; echo "|$- are the options|"; set +o nolog; echo "|$- are the options|"'
    > |
    > |uCf are the options|
    > $ dash -o debug -c 'set -fuC; echo "|$- are the options|"; set +o debug; echo "|$- are the options|"'
    > |
    > |uCf are the options|

    This turned out to be easy to fix. The routine producing the "$-"
    expansion failed to skip options for which there is no option letter,
    but only a long-form name. In dash, 'nolog' and 'debug' are currently
    the only two such options. Patch below.

    - Martijn

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In bbox ash, pipefail is the option which exhibited this.

Signed-off-by: Martijn Dekker <martijn@inlv.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>