bug#19475: Emacs-git build broken on Cygwin (ImageMagick)

[Angelo Graziosi]

The build of today Emacs-git 
(emacs-01827de4518c8da974821da0439f2ad4984d49da.tar.gz) fails because it 
does not find the '-lMagickCore' library. Indeed recently there was an 
ImageMagick update (from -6.7.6.3 to 6.9.0.0) that has broken the build.

I flagged this on Cygwin list and it produced this thread:

https://cygwin.com/ml/cygwin/2014-12/msg00390.html
https://cygwin.com/ml/cygwin/2014-12/msg00391.html
https://cygwin.com/ml/cygwin/2014-12/msg00393.html
https://cygwin.com/ml/cygwin/2014-12/msg00394.html

For what I can understand, it seems that Emacs tries to link not only 
with '-lMagickCore-6.Q16' but also with '-lMagickCore': in the new 
ImageMagick package, libMagickCore.dll.a has been renamed 
libMagickCore-6.Q16.dll.a. As workaround this link

  libMagickCore.dll.a -> libMagickCore-6.Q16.dll.a

in /usr/lib fixes the issue but maybe it has to be done at configure 
level removing the '-lMagickCore' at link time..


Ciao,
 Angelo.