anchor.diff:          packageRequires = [ emacs ];
           meta = {
             homepage = "https://elpa.gnu.org/packages/posframe.html";
  +          license = lib.licenses.free;
  +        };
  +      }) {};
  +    project = callPackage ({ elpaBuild, emacs, fetchurl, lib }:
  +      elpaBuild {
  +        pname = "project";
  +        ename = "project";
  +        version = "0.1.2";
  +        src = fetchurl {
  +          url = "https://elpa.gnu.org/packages/project-0.1.2.el";
  +          sha256 = "0713hwim1chf6lxpg1rb234aa1gj92c153fjlc4jddp6dzzgn50d";
  +        };
  +        packageRequires = [ emacs ];
  +        meta = {
  +          homepage = "https://elpa.gnu.org/packages/project.html";
             license = lib.licenses.free;
           };
         }) {};
  
positive.code:       elpaBuild {
          pname = "uniquify-files";
          ename = "uniquify-files";
          version = "1.0.2";
          src = fetchurl {
            url = "https://elpa.gnu.org/packages/uniquify-files-1.0.2.tar";
            sha256 = "1vib79wsz5k94b9z0wiwhbzsdm70y9dla6szw2bb75245cx3kr0h";
          };
          packageRequires = [ emacs ];
          meta = {
  
negative.code:         packageRequires = [ emacs ];
          meta = {
            homepage = "https://elpa.gnu.org/packages/xr.html";
            license = lib.licenses.free;
          };
        }) {};
      xref = callPackage ({ elpaBuild, emacs, fetchurl, lib, project }:
        elpaBuild {
          pname = "xref";
          ename = "xref";
          version = "1.0.1";
          src = fetchurl {
            url = "https://elpa.gnu.org/packages/xref-1.0.1.el";
            sha256 = "17wlwilm2d1gvin8mkkqnpw2skjx0klxfs1pqpy8rrzdfpsb55li";
          };
          packageRequires = [ emacs project ];
          meta = {
            homepage = "https://elpa.gnu.org/packages/xref.html";
            license = lib.licenses.free;
          };
        }) {};
  