[PATCH] PR gdb/21574: Mention $SHELL and startup-with-shell on "help run"

[Eli Zaretskii]

> From: Sergio Durigan Junior <sergiodj@redhat.com>
> Cc: Eli Zaretskii <eliz@gnu.org>,
> 	Sergio Durigan Junior <sergiodj@redhat.com>
> Date: Wed, 14 Jun 2017 16:48:36 -0400
> 
> This simple patch updates the documentation of "help run" in order to
> mention that the shell used to start the inferior comes from the
> $SHELL environment variable.  It also mentions that this behaviour can
> be disabled by using the "set startup-with-shell off" command.
> 
> OK?

Yes, but instead of 'see the "$SHELL" environment variable', I'd
suggest to say 'specified by the "$SHELL" environment variable'.

Thanks.