anchor.diff:  
     mkCoqPackages_8_5 = self: let callPackage = newScope self; in rec {
       inherit callPackage;
  -    coq = coq_8_5;
  +    coq = callPackage ../applications/science/logic/coq {
  +      version = "8.5pl3";
  +    };
       coqPackages = coqPackages_8_5;
   
       coq-ext-lib = callPackage ../development/coq-modules/coq-ext-lib {};
  
positive.code:     camlp5 = ocamlPackages_3_12_1.camlp5_transitional;
      lablgtk = ocamlPackages_3_12_1.lablgtk_2_14;
    };
    coq_8_4 = callPackage ../applications/science/logic/coq/8.4.nix {
      inherit (ocamlPackages_4_02) ocaml findlib lablgtk;
      camlp5 = ocamlPackages_4_02.camlp5_transitional;
    };
    coq_8_5 = callPackage ../applications/science/logic/coq {
      version = "8.5pl3";
    };
    coq_8_6 = callPackage ../applications/science/logic/coq {};
    coq_HEAD = callPackage ../applications/science/logic/coq/HEAD.nix {};
    coq = coq_8_6;
  
    mkCoqPackages_8_4 = self: let callPackage = newScope self; in {
      inherit callPackage;
      coq = coq_8_4;
      coqPackages = coqPackages_8_4;
  
      contribs =
  
negative.code: 
    mkCoqPackages_8_6 = self: let callPackage = newScope self; in rec {
      inherit callPackage;
      coq = callPackage ../applications/science/logic/coq {};
      coqPackages = coqPackages_8_6;
  
      coq-ext-lib = callPackage ../development/coq-modules/coq-ext-lib {};
  