anchor.diff:            license = lib.licenses.free;
           };
         }) {};
  +    vc-backup = callPackage ({ elpaBuild, fetchurl, lib }:
  +      elpaBuild {
  +        pname = "vc-backup";
  +        ename = "vc-backup";
  +        version = "1.0.0";
  +        src = fetchurl {
  +          url = "https://elpa.gnu.org/packages/vc-backup-1.0.0.tar";
  +          sha256 = "0vcrbb4s1rzar9q882kfcslycxvycp61923sg82i29b7yd0yrgdr";
  +        };
  +        packageRequires = [];
  +        meta = {
  +          homepage = "https://elpa.gnu.org/packages/vc-backup.html";
  +          license = lib.licenses.free;
  +        };
  +      }) {};
       vc-hgcmd = callPackage ({ elpaBuild, emacs, fetchurl, lib }:
         elpaBuild {
           pname = "vc-hgcmd";
  
positive.code:         packageRequires = [ queue ];
          meta = {
            homepage = "https://elpa.gnu.org/packages/tNFA.html";
            license = lib.licenses.free;
          };
        }) {};
  
negative.code:       elpaBuild {
          pname = "tramp";
          ename = "tramp";
          version = "2.5.1.2";
          src = fetchurl {
            url = "https://elpa.gnu.org/packages/tramp-2.5.1.2.tar";
            sha256 = "0p8m8prxrvrr455ahb626c1dry04m80y017h16ngr4i5ais0r85g";
          };
          packageRequires = [ emacs ];
          meta = {
  