anchor.diff:      patchShebangs .
       sed -i $JLIB/bin/profile.ijs -e "s@'/usr/share/j/.*'@'$out/share/j'@;"
   
  -    ./build_all.sh
  +    j64x="${j64x}" ./build_all.sh
   
       cp $SOURCE_DIR/bin/${platform}/j${bits}*/* "$JLIB/bin"
     '';
  
positive.code: { stdenv, fetchFromGitHub, readline, libedit, bc }:
  
  stdenv.mkDerivation rec {
    pname = "j";
  
negative.code:     if stdenv.isLinux then "linux" else
      if stdenv.isDarwin then "darwin" else
      "unknown";
    variant = if stdenv.isx86_64 && avxSupport then "avx" else "";
  
    j64x="j${bits}${variant}";
  
    doCheck = true;
  
  