anchor.diff:  
   buildGoPackage rec {
     name = "alertmanager-${version}";
  -  version = "0.5.1";
  +  version = "0.6.0";
     rev = "v${version}";
   
     goPackagePath = "github.com/prometheus/alertmanager";
  
positive.code:     inherit rev;
      owner = "prometheus";
      repo = "alertmanager";
      sha256 = "1z0f8jqbd4v00634qcs41h1zb70ahl63svlzn33gavripk84hwzq";
    };
  
    # Tests exist, but seem to clash with the firewall.
  
negative.code:        -X ${t}.GoVersion=${stdenv.lib.getVersion go}
    '';
  
    postBuild = ''
      $NIX_BUILD_TOP/go/bin/artifacts
    '';
  
    postInstall = ''
      rm $bin/bin/artifacts
      mkdir -p $bin/share/man/man1 $bin/etc/bash_completion.d
      cp -v amtool*.1 $bin/share/man/man1
      cp -v amtool_completion.sh $bin/etc/bash_completion.d
    '';
  
    meta = with stdenv.lib; {
      description = "Alert dispatcher for the Prometheus monitoring system";
      homepage = https://github.com/prometheus/alertmanager;
  