[PATCH] Make sure GDB uses a valid shell when starting the inferior and to perform the "shell" command

[Eli Zaretskii]

> From: Andreas Schwab <schwab@linux-m68k.org>
> Cc: sergiodj@redhat.com,  simon.marchi@ericsson.com,  gdb-patches@sourceware.org
> the set of non-shells is finite, because they will match a line in
> /etc/shells.

I'm okay with looking up non-shells in /etc/shells, but that's not
what the proposed patch does.  It just compares the shell's file name
with a list of known "invalid" shells.  It doesn't even mention
/etc/shells, in fact, not even in the documentation parts of the
patch.