The comments in magick/magick-config.h indicate that the header file is not autogenerated (fixed stuff).
However, a "make distclean" appears to remove this file, effectively breaking future builds.
make distclean removes magick-config.h
Re: make distclean removes magick-config.h
We can reproduce the problem you posted and have a patch in ImageMagick 6.8.5-5 Beta available by sometime tomorrow. Thanks.