Disable gcc arch optimization
    
    By default, ImageMagick tries to optimize its build for the build host's
    CPU and passes -mcpu to the compiler. This cannot be used in Fedora
    since we need to support other CPUs as well, not just whatever happens
    to be used on the build host. This commit disables it by passing
    --without-gcc-arch to configure.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1213828