bug#39181: 27.0.50; [PATCH] Allow users to store & restore gdb-mi layout

[Eli Zaretskii]

> From: Yuan Fu <casouri@gmail.com>
> Date: Sat, 18 Jan 2020 15:57:32 -0500
> 
> Right now if a user wants to use gdb with many windows, the only layout 
> option is the default 6-window layout.

This is not entirely accurate.  The user could start "M-x gdb"
normally, then selectively display some of the other windows via the
Gud->GDB-Windows or Gud->GDB-Frames menus.

> This patch  allows a user to save her own layout, and use this layout in 
> gdb-mi sessions.

I'd prefer to extend the existing capability by adding a feature, both
in the menu bar and as a command, to save and restore the window
configuration set via the above-mentioned existing facilities.  WDYT?

Please also fix all the minor nits I mentioned in review of your
previous patches: quoting, 2 blanks between sentences, complete
sentences in comments and log messages, etc.  Last, but not least,
please don't break a single patch into several separate ones, unless
each one of the separate patches can make sense if applied on its own.

Thanks.