backtick to NOT set variable

[Max Ivanov]

Hi,

can backtick (or combination of other scripts commands) can be  to NOT
set env var on error?

here is a toy example:

#!./bin/execlineb -S0
backtick -n MAYBE_ARG { /bin/false }
import -u MAYBE_ARG
s6-echo ${MAYBE_ARG} $@


when running under strace I see that it passes empty arg "" to command.

I could add `-s` flag, to `import` and it solves problem for an empty value,
but it also splits non empty value which is not desirable.


Thanks