bug#33016: 26.1; (make-process ...) doesn't signal an error, when executable given as absolute Windows path does not exist

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@gmail.com>
> Date: Mon, 8 Apr 2019 14:34:41 -0400
> Cc: 33016@debbugs.gnu.org
> 
> >     M-x eval-expression RET
> >       (make-process :name "test" :command '("c:/No Such Command"))
> >
> > will merely display in the echo-area message:
> >
> >     eval: Spawning child process: Invalid argument
> 
> The confusing thing here is that the error is signaled between
> block_input()...unblock_input(), which prevents the debugger from
> triggering. E.g., the "-unless-debug" part in the expression below
> appears not to work, even though the error flows normally in other
> respects:
> 
> (condition-case-unless-debug err
>     (make-process :name "test" :command '("c:/No Such Command"))
>   (error (list :error err)))
> ;=> (:error (file-error "Spawning child process" "Invalid argument"))
> 
> The attached patch fixes this by moving the signal to after the 
> unblock_input().

Thanks, but could we have a test for this, please?