anchor.diff:  { fetchurl, stdenv, gnum4, texinfo, texLive, automake }:
   
   let
  -  version = "9.1";
  +  version = "9.1.1";
     bootstrapFromC = ! (stdenv.isi686 || stdenv.isx86_64);
   in
   stdenv.mkDerivation {
  
positive.code:       url = "mirror://gnu/mit-scheme/stable.pkg/${version}/mit-scheme-c-${version}.tar.gz";
        sha256 = "1661cybycfvjjyq92gb3n1cygxfmfjdhnh3d2ha3vy6xxk9d7za9";
      };
  
    configurePhase =
      '' cd src
         ./configure --prefix="$out"
  
         cd ../doc
         ./configure --prefix="$out"
         cd ..
       '';
  
    buildPhase =
      '' cd src
  
negative.code:     if stdenv.isi686
      then fetchurl {
        url = "mirror://gnu/mit-scheme/stable.pkg/${version}/mit-scheme-${version}-i386.tar.gz";
        sha256 = "1bigzzk0k08lggyzqp4rmyvbqhhs3ld4c7drfp22d5qnkbvvzh4g";
      } else if stdenv.isx86_64
      then fetchurl {
        url = "mirror://gnu/mit-scheme/stable.pkg/${version}/mit-scheme-${version}-x86-64.tar.gz";
  