Re: Building Emacs on MSYS2

[Eli Zaretskii]

> From: Óscar Fuentes <address@hidden>
> Date: Sat, 16 Apr 2016 00:11:30 +0200
> 
> You can also try to see what happens if you omit the patches. Remove
> image.c.diff from `source' and the corresponding SHA hash from
> `sha256sums' (the hashes of the files are listed in the same order as in
> `sources'). See if the build breaks. See if imagemagick is detected. See
> if you can use imagemagick from the resulting package. Report your
> results.

The Imagemagick build is not officially supported in the MS-Windows
build, because no one submitted patches to make it behave like all the
other optional image libraries.  By that I mean: be able to run an
Emacs binary built with Imagemagick support on a system that doesn't
have the Imagemagick DLLs installed.  AFAIU, the image.c.diff hack
allows one to build Emacs with Imagemagick, but the resulting binary
will refuse to run on a system where it cannot load the Imagemagick
DLLs at startup.  That is not how we handle optional libraries in the
Windows build.

So the right way of handling this problem is to modify the Emacs
Imagemagick support code in image.c so that it uses LOAD_DLL_FN etc.
(There's one complication with Imagemagick: it needs to load 2 DLLs
rather than one, and figuring out how to deal with that is part of the
job.)