bug#68272: [PATCH] Fix -1 leaking from C to lisp in 'read-event' etc.

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

>> > IOW, what about callers that actually _want_ to know when the macro
>> > ends prematurely?
>> I couldn't find any, really.
> ??? calc is one, obviously.

I don't think so: AFAICT the tests there were added simply
because they had to do something with this -1 return value.

Other places deal with it differently (e.g. by setting
`executing-kbd-macro` to nil), so *maybe* the specific way they deal
with it is indicative of intent, but from where I stand it looks like
they just chose that behavior arbitrarily.

I can't think of a good UI reason why they'd *want* to signal an error
when a kmacro ends in the middle of a `Z` thingy: it's an acceptable
behavior but it's not clearly superior to just continuing reading the
Z thingy from live input (I'd even tend to think that continuing is
a better choice since it lets users use kmacro that provide the first
part of a Z thingy and let the user finish it).


        Stefan