bug#3016: 23.0.92.2; offer to make a directory when saving if it is needed

[Glenn Morris]

Version: 24.4

Daniel Clemente wrote:

> 1. Do: C-x C-f /tmp/doesnotexist/myfile RET. Emacs tells you about
> make-directory
> 2. Type something.
> 3. C-x C-s. Error: no such directory
>
> I suggest that Emacs not only tell the user about make-directory, but
> actually ask him/her in a y-n question if the directory should be
> created. This should happen on save.

Sorry for the huge delay. This seems like a good idea, so I did it.