Re: 64-bit build on Windows

[Eli Zaretskii <eliz@gnu.org>]

> From: Fabrice Popineau <fabrice.popineau@gmail.com>
> Date: Sun, 22 Jan 2017 21:38:39 +0100
> Cc: Juanma Barranquero <lekktu@gmail.com>, Óscar Fuentes <ofv@wanadoo.es>, 
> 	Emacs developers <emacs-devel@gnu.org>
> 
>  > + '(magickwand "libMagickWand-7.Q16HDRI-0.dll" "libMagickWand-7.Q16-0.dll")
>  > + '(magickcore "libMagickCore-7.Q16HDRI-0.dll" "libMagickCore-7.Q16-0.dll")
> 
>  Does this mean we will only support ImageMagick 7.x and later on
>  Windows? If so, the configure-time test should be changed, since it
>  currently allows 6.x, I think.
> 
> Given that MSYS2 itself has switched to IM7, I don't see the point to keep support forIM6.

But ImageMagick libraries were available as DLLs regardless of what
MSYS2 did or didn't do, so I think we should have associations for
those binaries as well, for ImageMagick 6.x.

>  > @@ -8406,7 +8776,7 @@ imagemagick_compute_animated_image (MagickWand *super_wand, int
>  ino)
>  > PixelWand **source, **dest;
>  > size_t source_width, source_height;
>  > ssize_t source_left, source_top;
>  > - MagickPixelPacket pixel;
>  > + PixelInfo pixel;
> 
>  What is this about?
> 
> AFAIR they changed the names of a few structures.

Then this should be conditioned on ImageMagick version, and we
probably need a Lisp variable holding the version number to look for
DLLs that are specific to the version against which Emacs was
compiled, similar to libpng-version.