anchor.diff:      cp -r .  "$out/share/ccl-installation"
   
       mkdir -p "$out/bin"
  -    echo -e '#!/bin/sh\n'"$out/share/ccl-installation/${CCL_RUNTIME}"' "$@"\n' > "$out"/bin/"${CCL_RUNTIME}"
  +    echo -e '#!${stdenv.shell}\n'"$out/share/ccl-installation/${CCL_RUNTIME}"' "$@"\n' > "$out"/bin/"${CCL_RUNTIME}"
       chmod a+x "$out"/bin/"${CCL_RUNTIME}"
       ln -s "$out"/bin/"${CCL_RUNTIME}" "$out"/bin/ccl
     '';
  
positive.code: 
  let
    options = rec {
      /* TODO: there are also MacOS, FreeBSD and Windows versions */
      x86_64-linux = {
        arch = "linuxx86";
        sha256 = "0hs1f3z7crgzvinpj990kv9gvbsipxvcvwbmk54n51nasvc5025q";
  
negative.code:       runtime = "armcl";
        kernel = "linuxarm";
      };
      x86_64-darwin = {
        arch = "darwinx86";
        sha256 = "5adbea3d8b4a2e29af30d141f781c6613844f468c0ccfa11bae908c3e9641939";
        runtime = "dx86cl64";
        kernel = "darwinx8664";
      };
      i686-darwin = {
        arch = "darwinx86";
        sha256 = x86_64-darwin.sha256;
        runtime = "dx86cl";
        kernel = "darwinx8632";
      };
      armv6l-linux = armv7l-linux;
    };
    cfg = options.${stdenv.system};
  