anchor.diff:        owner  = "oracle";
         repo   = "graal";
         rev    = "vm-${version}";
  -      sha256 = "1hcs4m6ailapgi3bikav1i517vqn5pn595cyqqjfvlnkjwihbnc3";
  +      sha256 = "1fada4awrr8bhw294xdiq4bagvgrlcr44mw6338gaal0ky3vkm0p";
       };
       buildInputs = [ mx zlib mercurial jvmci8 ];
       postUnpack = ''
  
positive.code: 
        export MX_ALT_OUTPUT_ROOT=$NIX_BUILD_TOP/mxbuild
        export MX_CACHE_DIR=${makeMxCache graal-mxcache}
        ( cd substratevm
  
          mkdir -p clibraries
  
negative.code:                                   install -D ${fetchurl { inherit url sha1; }} $out/${name}
                                    echo -n ${sha1} > $out/${name}.sha1
                                  '') list}
          find $out -exec touch -c -m -r '{}' --date="1980-01-01" '{}' \;
        '';
      };
  
  