ImageMagick patch

[Gábor Csárdi]

Hi,

the attached patch fixes a freeze in ImageMagick, which we noticed
when using the new r_base. It seems that ImageMagick's openMP support
is not great, e.g. brew turns it off as well:
https://github.com/Homebrew/homebrew-core/blob/433cedc2bd5e83f07ea826fefc90685dbb11a4b6/Formula/imagemagick%406.rb#L41-L44

I also added --disable-dependency-tracking, otherwise the build fails.

It also updates to the latest stable ImageMagick version.

Do you think this could be added to OpenCSW?

Thanks much,
Gabor