bug#7575: gdb command history saving

[Glenn Morris]

Version 24.1

Glenn Morris wrote:

> You could add something like the following to gdb-mode-hook:
>
>   (setq comint-input-ring-file-name "~/.gdbhist")
>   (comint-read-input-ring t)
>
> shell-mode tries to do this by default; perhaps gdb-mode should do
> similar.

I've added this to M-x gdb.