bug#12615: 24.2.50; Non-ignored case in insert-char

[Juri Linkov]

>> Maybe to fix all them at once, `read_minibuf' should make
>> a local variable `completion-ignore-case' in the minibuffer
>> and copy its value from the original buffer?
>
> That might be a good idea.
> I'd guess only completing-read would need to do it, rather than
> read_minibuf.

Then `completing-read-default' would be a good place too
(anyone who overrides `completing-read-function' have to copy most of
code from `completing-read-default' anyway).

> Tho we might still want to make it possible to specify case-irrelevance
> in the completion table itself.

I suppose you mean specifying `completion-ignore-case' in `metadata'.
This could help to avoid problems with buffer-local bindings of
`completion-ignore-case'.