Re: Warnings in mingw64 build on emacs-28 branch

[Eli Zaretskii <eliz@gnu.org>]

> From: Óscar Fuentes <ofv@wanadoo.es>
> Date: Sun, 07 Nov 2021 20:57:38 +0100
> 
> > I don't understand why the compiler thinks the object must be
> > initialized for its pointer to be valid.  Does the compiler assume
> > something about what VirtualQuery does?  Why does it think the
> > function will dereference the pointer?
> 
> The warning says "may be used uninitialized". The compiler doesn't know,
> it sees something suspicious and speaks up. That's with -Wall, without
> it, the compiler remains silent.
> 
> I guess the MinGW headers should be annotated with whatever decoration
> gcc uses to convey that the pointer is not dereferenced.
> 
> Or we can initialize `m' to zero, which will silence the warning and is
> a good practice in general when working with the Windows API.

I actually tend to think that this is a compiler bug that should be
reported to the GCC folks.