bug#43572: Feature request: make it possible to choose whether the first lines of the minibuffer should be displayed instead of the last ones

[Gregory Heytings via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

>
> There are more callers of resize_mini_widow than just those.  It is not 
> safe to assume that this can be handled only inside read_minibuf.
>

Please have a look at my corrected patch.  It handles this inside 
read_minibuf() *and* read_minibuf_unwind(), which AFAICS should make the 
change to start_display_at_beginning_of_minibuffer last only for the time 
it should last.  If that's not the case, could you please provide a 
recipe?  I'm willing to improve the patch a second time if it's necessary.

>
> So I agree with Stefan that the text inserted into the minibuffer should 
> itself indicate to the display engine that it wants to be displayed 
> starting at BOB.  That way we don't have to worry about inadvertently 
> affecting other users of the mini-window.
>

That's a possibility indeed, and I agree that it would be even better, but 
as I said this is several orders of magnitude harder to implement, and 
unlikely to happen in a near future.