anchor.diff:  
   let
     meta = {
  -    homepage = http://www.gnu.org/software/ghostscript/;
  +    homepage = "http://www.gnu.org/software/ghostscript/";
       description = "GNU Ghostscript, a PostScript interpreter";
   
       longDescription = ''
  
positive.code:   mainlineSrc = {
      name = "ghostscript-9.05";
      src = fetchurl {
        url = http://downloads.ghostscript.com/public/ghostscript-9.05.tar.bz2;
        sha256 = "1b6fi76x6pn9dmr9k9lh8kimn968dmh91k824fmm59d5ycm22h8g";
      };
      meta = meta // {
        homepage = http://www.ghostscript.com/;
        description = "GPL Ghostscript, a PostScript interpreter";
      };
  
  
negative.code: 
    fonts = [
      (fetchurl {
        url = "mirror://gnu/ghostscript/gnu-gs-fonts-std-6.0.tar.gz";
        sha256 = "1lxr1y52r26qjif8kdqkfhsb5llakdcx3f5b9ppdyn59bb83ivsc";
      })
      (fetchurl {
        url = "mirror://gnu/ghostscript/gnu-gs-fonts-other-6.0.tar.gz";
        sha256 = "1cxaah3r52qq152bbkiyj2f7dx1rf38vsihlhjmrvzlr8v6cqil1";
      })
      # ... add other fonts here
  