[PATCH] env: add -n/--name option

[Matheus Afonso Martins Moreira]

> BTW it seems like SHLVL can be unset here.

I tried it but it doesn't seem to be the case.
Am I doing it incorrectly?

    $ env -i bash -c 'exec -a program ./program'
    program
    PWD=/data/data/com.termux/files/home/dev/coreutils
    SHLVL=0

    $ env -i bash -c 'unset SHLVL; unset PWD; exec -a program ./program'
    program
    SHLVL=0

> Perhaps --title would be more appropriate, given "name" is mentioned
> quite a bit already in the description.

I can send an updated patch!
May I also suggest --argv0 option?

> An edge case is we may want to support
> allowing to specify a NULL argv[0].

Yes. How should such a NULLL value be denoted in the command line?
Should there be a separare --null-argv0 option?

Thank you for the feedback.

Matheus Moreira