OTP 27 RC3's "erl -man" tries to look up docs for --

[jrfondren]

Describe the bug
erl man lists shows the manpage for 'lists' (if present), and then shows an error appropriate for the command erl man --

To Reproduce

# OTP 27 RC3
$ PAGER=cat erl -man lists >/dev/null; echo $?
No manual entry for --
16

# OTP 27 RC1 (without docs)
$ PAGER=cat erl -man lists >/dev/null; echo $?
No manual entry for lists
No manual entry for --
16

# OTP 26
$ PAGER=cat erl -man lists >/dev/null; echo $?
0

Expected behavior
erl -man lists should only look up the documentation for the lists module.

Affected versions
Confirmed to be in OTP 27 RC3 and RC1

Additional context
-- is the conventional "stop processing arguments here" argument under Unix.

This happens within erlexec and isn't caused by asdf or another wrapper:

$ ~/.asdf/installs/erlang/27.0-rc1/erts-14.3/bin/erlexec -man lists
No manual entry for lists
No manual entry for --

And is not due to erlexec looping over module names, but due to "--" getting passed as an arg to man:

18:40:54 execve("/usr/bin/man", ["man", "lists", "--"],

The sep handling was recently changed, but the manpage code wasn't at all. I guess that "--" wasn't getting added to argv before in this code path. A simple fix is to not reuse argv in the execvp call, which would change behavior for anyone (probably nobody) who was passing extra arguments to man after the module name.

[garazdawi]

Thanks for the report. Fixed available in #8478.